How to Balance the Rotating Assembly for a Single Cylinder Engine to Reduce Annoying and Dangerous Vibration

The basis of improved engine performance is precision workmanship. Every effort must be made to reduce friction and step up power. It must be remembered that extreme accuracy in setting the ignition timing, carburetion, together with a quality valve job, will give better than average performance. Contributing largely to stepped-up performance is precision balancing of the piston assembly and the connecting rod to the crankshaft counterweights. A special dynamic balancing machine or an electronic digital scale is used for balancing the piston assembly/rod to the crankshaft so the total weight of the piston assembly/connecting rod is exactly the same as the crankshaft's counterweights. Also, precision balancing of the rotating assembly and flywheel and low vibration saves wear and tear on internal engine components and attached external equipment.

Go here to learn how to balance a small engine crankshaft as close as possible: Crank Balancing Explained Single Cylinder. (YouTube video by MiniDragBike.) (Added 4/15/22)

If bolts, screws or nuts on the engine or tractor frame loosen due to engine vibration, there's no need to apply Loctite on the threads of the fastener. Just install a split lock washer of the correct size that fits the fastener (under the head or nut) then torque the fastener to specs. The lock washer will guarantee the fastener will stay tight. Or a self-locking nut can be used instead.

Here's some important information to remember - (Updated 3/7/18)

First of all, Kohler (and all other engine manufacturers) [obviously] balance their engines at the factory. The crankshafts' counterweights are equally balanced to the weight of the piston assembly to reduce engine vibration. The crankshafts that's are used in the K301, K321, K341 and K361 engines have the same stroke. The crankshaft in the K321 and K341 Kohler engine, and the K361 Kohler engine are identical (except perhaps for the PTO end). Therefore, they're balanced the same and can be used in either engine. All these engines have the same stroke, too. Only the counterweights are different. More metal is removed (drilled and machined off) from the counterweights for the K301 engines, which use a lighter weight piston than the K321, K341 and K361 pistons. The K301 crankshaft and piston assembly are a balanced set. Kohler use the same identical piston in their K341 and K361 engines. Although the connecting rods in these engines are made of different material, they weigh the same. Therefore, the crankshafts are balanced the same. The wrist pin is narrower in the K341 and K361 piston, making them weigh pretty much the same as the K321 piston and wrist pin. https://en.wikipedia.org/wiki/Balancing_of_rotating_masses

HOWEVER, certain factory-type pistons come with a heavy wall wrist pin (weighs more), and others come with a thin wall wrist pin (weighs less). I believe that all OEM Kohler pistons come with a thin wall wrist pin, and most (or all) imported pistons come with a thick wall wrist pin. I'm not sure if there's a difference in the weight of the pistons themselves, and if this is why the manufacturer included a heavy or lightweight wrist pin to compensate for the weight of the piston to maintain engine balance. Anyway, to reduce the chance of excessive engine vibration, use the heavy wall wrist pin in an engine that's going to run up to 4,000 RPM, and use the thin wall wrist pin in an engine that operates at a higher RPM.

The same crankshaft can be used with the K321, K341 and K361 piston assembly. If both counterweights on your crankshaft aren't machined off flat, then it's a 14 or K341 crank. If they are machined off, then it's a K301 crankshaft. And a K301 crank shouldn't be used with a K321 or K341/K361 piston assembly. The engine will vibrate more than usual and because of the heaver piston assembly, the connecting rod could stretch and eventually break. If a K321, K341 or K361 crank is used with a K301 piston, because of the heavier counterweights, the crankshaft could eventually break. Because there's one opposing force working against the other. ("For every action, there's an equal and opposite reaction." - Newton's third law of motion.)

In other words, the K301 crankshaft is balanced differently from the K321, K341 and K361 engine crankshafts. Although the stroke and rod journal are the same, the counterweights on the K301 crank are different. The K301 piston assembly weighs less than the K321 and K341/K361 piston assemblies. Therefore, the K321, K341 and K361 crankshafts require more metal on the counterweights to balance out equally. And K321, K341 and K361 crankshafts are all balanced the same, which means that they're interchangeable between the K321, K341 and K361 engines.

Because of it's shorter stroke, the K241 crankshaft is different from the K301, K321, K341 and K361 cranks. The K301 crankshaft's counterweights are machined flat for the lighter-weight K301 piston/rings assembly, while the K321, K341 and K361 crankshaft's counterweights are rounded for the heavier K321, K341 and K361 piston/rings assemblies. The same crankshaft is used in the K321, K341 and K361 engines because their piston/rings assemblies weigh the same.

The diffence between the 12hp crankshaft and the 14hp and 16hp crankshafts.

There's two types of K301 Kohler crankshafts. One is the early type. Its counterweights are the same width, and they're rounded with holes drilled. (Certain K241 crankshafts are like this, too.) The later K301 cranks have one wide and one narrow counterweight and both of them are machined flat to lighten them.

The crankshaft to the right -> is the very early model K301 version, because the counterweights are the same width. This crankshaft was produced in 1966-early 1969, before the K321 (and the K341 and K361, which share the same crankshaft because the piston assemblies are balanced the same) came into production. The K321 went into production in late 1969. The counterweights on the crankshaft for the K321, K341 and K361 engines, one is narrow and the other is wide. When the K321, K341 and K361 engines were manufactured, Kohler stopped making this type of crank and used the K321, K341 and K361 crankshafts in the K301. They just machined part of the counterweights off and drilled a few holes to bring it into balance with the lighter weight K301 piston assembly. And I have experienced certain K301 engines vibrate excessively for some unknown reason. I had to have the crankshaft dynamically and precision spin-balanced and then the engine ran smooth with a lot less vibration. This goes to show that the technology for single cylinder engine balancing during the 1960's isn't like it is today.

K-series VS Magnum Crankshafts -
A K-series K301 crankshaft cannot be used with a K321, K341 or K361 piston/rings assembly without adding a lot of weight to the counterweights because the K301 crankshaft is balanced too light. The opposite would need to be done if a K321, K341 and K361 crankshaft is used with a K301 piston/rings assembly, or the engine would vibrate more than normal. If a K-series K301 crankshaft is going to be used in a K321, K341 or K361 piston assembly, it would need to precision spin-balanced.
The Magnum 3-Balance Gear System -
The Magnum M12, M14 and M16 crankshafts are interchangeable with the older K-series K301, K321 and K341 crankshafts, but... the Magnum crankshafts are all basically balanced the same... for a K301 piston/rings assembly. Certain Magnum engines use three counterbalance gears instead of two, like certain K-series engines do. Just like the K-series, the two balance gears beside the crankshaft in both the K-series and Magnums are meant to reduce the side-thrust or the side-to-side vibration of the counterweights only on the crankshaft. But the lower balance gear in certain Magnum engines is used to reduce the up-and-down vibration of the piston/connecting rod assembly and counterweights, because the Magnum counterweights are too light for the K321, M14, K341 and M16 piston/rings assemblies. Go here to learn how to correctly align the three balance gears in a Magnum engine: Kohler Three Gear Balance Gear System Service Bulletin 208.pdf. (Adobe Reader required.)
For the heavier M14 and M16 Mahle piston/rings assemblies, the bottom balance gear simulates additional weight on the counterweights of the crankshaft so the engine will run with less vibration. If the Magnum balance gears are left out or removed from the engine, the engine will vibrate excessively! But if the balance gears are purposely left out, such as for open RPM competition pulling, the rotating assembly would need to be dynamically and precision spin-balanced to reduce dangerous vibration. The older K-series engines will not likely to vibrate more than it did before with the balance gears removed.
And if a Magnum crankshaft is replaced with a K-series crankshaft, the Magnum balance gears shouldn't be used with the K-series crankshaft. If they are used, the engine may vibrate a lot.
If a Magnum (M12, M14 or M16) crankshaft require three balance gears, it can be used without the balance gears in a K-series block if it is dynamically and precision spin-balanced to reduce the vibration (with the connecting rod and piston/rings assembly) on a crankshaft balancing machine.
And I have no idea why Kohler changed the crankshaft balancing with the Magnum single cylinder engines to a three balance gear balancing system. It make no sense at all to me. I mean, the way the older K-series engines was balanced worked great. But anyway, it'll be best to leave out the balance gears and have the rotating assembly (crankshaft, piston/rod assembly) dynamically and precision spin-balanced. By having this done, the engine, with no doubt, should run much smoother and possibly last longer.
The early K-series crankshafts have a 3/16" wide slotted [flywheel] keyway and a 5/8" diameter threaded stud w/nut to retain the flywheel, and the later K-series and all Magnum crankshafts have a #5 Woodruff [flywheel] keyway and a 3/8" bolt to retain the flywheel.

The K241 and M10 crankshafts have a shorter stroke (2.875") than the K301, K321, K341 and K361 cranks (3.25"). The K241 and M10 crankshafts are in a class by themselves. Therefore, they can't be used in combination with a K301, K321, K341 and K361 connecting rod or piston assembly without extensive machine work and precision balancing. And the K301, K321, K341 and K361 cranks can't be used with a K241 connecting rod or piston assembly without extensive machine work and precision balancing.

Identifying the Differences in the Kohler K-series and Magnum Single Cylinder Engine Crankshafts -

To identify the K241, M10, K301, M12, K321, M14, K341, M16 and K361 Kohler crankshafts, the K241 and M10 cranks have a shorter stroke than the other cranks. You can compare a K241 crank to a K301, K321, K341 and K361 crank by placing them side by side, and with the counterweights down, looking at the bottom part of the rod journal, the journal on the K241 will be closer to the main journals. (3/8" of difference in stroke.)
The K301 and M12 crankshaft is different from the K321, M14, K341, M16 and K361 cranks because the counterweights are machined off for the lighter-weight K301 and M12 piston assembly. NOTE: Some K241 cranks also have the counterweights machined off like the K301 does, and some don't.
And the K321, K341 and K361 cranks are identical in weight and appearance. Some may have a few more holes drilled into the counterweights, but that's the only difference.
Because of it's lighter weight piston assembly, the K301 crankshaft is balanced differently or lighter from the K321, K341 and K361 cranks. If installed in a K321, M14, K341, M16 and K361, the engine will vibrate more than usual and after a while, the connecting rod could break. If a K321, K341 or K361 crank is used in a K301 engine, the engine will vibrate more than usual and after a while, the crankshaft could break. So it's important that the right parts are correctly matched for durability of the engine, and not to mention operator comfort.

Kohler's Dynamic Counterbalance System -

Kohler's Dynamic Balance System Various Kohler engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361 use a Dynamic Balance System, which are two out-of-balance gears that rotate on stub shafts that's pressed into the PTO side of the engine block. These counterbalance gears rotate in opposite direction of the crankshaft. These gears reduce the rotating side thrust (vibrating affect) of the crankshaft. Most Kohler K-series K241 and Magnum M10 engines came from the factory without balance gears. Only thirteen K241 engines came from Kohler with balance gears installed. These engines have the specification numbers: 46578, 46634; (Allis Chalmers); 46590 (Yazoo); 46593, 46608, 46633 (John Deere); 46664, 46718, 46764, 46803 (Simplicity); 46809, 46810 (Grainger); and 46838 (Ingersoll Rand). And only four M10 engines came from Kohler with balance gears installed. These engines have the specification numbers: 461509 (Ingersoll Equipment); 461513, 461526, 461550, 461551 (Ingersoll Rand); 461534 (Cub Cadet); and 461543 (Compair Kellogg). All other specification numbers for the K241 and M10 engines have no balance gears. However, if your engine vibrates a lot, it should to be dynamically and precision spin-balanced. But most K241 and M10 engines (without balance gears) run smoothly from the factory without balance gears originally installed.

Unless a heavier crankshaft is used (than the original one that came in the engine), in some K241 Kohler engines, it will vibrate more if the balance gears are left out. But the K301, K321, K341 and K361 engines will not vibrate much more without the balance gears. And the balance gears in the K241 engine are the same as the ones used in the K301, M12, K321, M14, K341, M16 and K361 engines. They have the same OEM Kohler part number.

NOTE: For reasons unknown why Kohler did this, when the balance gears are removed, with the stock factory cast crankshaft, OEM connecting rod and OEM piston/rings assembly, certain K301 engines will vibrate more than usual at any RPM, while other K301 engines with factory rotating parts that didn't originally come with balance gears don't vibrate much at all. The counterweights on the K301 crankshafts that vibrate more and the ones that don't vibrate as much look almost the same, too. Only the K301 engines experience this. Most K321, K341 and K361 engines don't vibrate more without the balance gears, even at high RPM or at wide open throttle.

For most single cylinder Kohler engines, balance gears isn't necessary.

Leaving out the balance gears shouldn't have a noticeable effect on engine vibration, but sometimes they help to reduce engine vibration. So if you choose to reinstall or leave them in an engine that will never turn more than 4,000 RPM (this is the maximum RPM for pulling in stock classes or for general lawn and garden use), make sure that the bearings in the [balance] gears and the stub shafts that they spin on are in good condition. If the bearings are worn and if the balance gears wobble, they'll wear the crankshaft gear teeth and they could break, possibly destroying the engine. By the way - the balance gears alignment tool (timing gage) is no longer available from Kohler. If you find a good used one or a new one from a Kohler dealer's old stock, the Kohler part numbers are 25 455 06-S, 10355 or Y-357. It's much easier to use this plastic tool when aligning the balance gears in time with the crankshaft. See the animated image to the right -> for correct identification of this tool.

Once, just for curiosity, after I've rebuilt a K301 Kohler engine, I've ran the engine with the balance gears installed and correctly aligned with the crankshaft. Then I removed the balance gears just to see if the engine would vibrate more. (It wasn't a lot of work to remove the gears. I removed the oil pan, snap rings, washers and spacers, rotated the crankshaft to clear the balance gears, and lifted the gears right out.) Anyway, I found that without the balance gears, the engine vibrated EXACTLY the same as when the balance gears were installed! Wonder why Kohler installed them in the first place. ????

Counterbalance gears does no good to install them. Most Kohler engines don't come with them and they do very little to help reduce engine vibration. When left out, the engine will not vibrate more than usual. Besides, being balance gears are made of cast iron and operate out of balance on a single needle bearing, they've been known to break and destroy the crankshaft, cam and engine block. I've seen this happen a few times. Therefore, I highly recommend leaving them out.

By the way - I've seen balance gears in the K241, K301, K321, K341 and K361 engines, but not every one of these engines have balance gears. I've even seen some Kohler Magnum M16 engines have three balance gears! Anyway, it seems that Kohler was selective in which engines they put them in. Perhaps they only put them in engines that was installed in a "luxury-type" of garden tractor to help reduce operator discomfort. And every balance gear I've ever seen appear to be exactly the same weight and design.

If a stock OEM-type piston assembly and connecting rod is going to be (re)used, there's no need to re-balance the crankshaft/piston/rod assembly if these gears are removed. If you want, leave the balance gears out. Actually, they're more trouble reinstalling and align with the crankshaft than they're worth. You won't notice that much difference in the vibration of the engine, either. It won't damage anything and it won't hurt anything. The engine will operate just fine without them.

Remove the Balance Gears Without Disassembling the Engine -

The balance gears in a Kohler engine can be removed without removing the crankshaft. To do this, first, remove the oil pan, and use high quality, heavy duty snap ring pliers with 90° tips to remove the [heavy gauge] snap rings that retain the balance gears, and rotate the crankshaft so the counterweight will clear the balance gears. However, the counterweights on the K301 crankshaft are machined off, allowing room to remove the balance gears. But on the K321, K341 and K361 engines, one of the counterweights may be in the way. If it is, try driving the pins into the crankcase from outside the PTO end of the block, and use clear RTV silicone adhesive sealant to securely plug the holes in the block. Because the snap rings that retain the balance gears are actually thicker than ordinary ones, which makes them harder to expand. A flat screwdriver may need to be wedged under each snap ring to help pry them off the stub shafts. (I've been there and done this many times. And it's difficult each time.) Be sure to remove the spacers (if equipped) and shims from the shafts, too. By the way - the shims from removal of the balance gears can be used as camshaft shims to set the cam-to-block clearance on the K241-K361 engines.

Don't (re)install the balance gears in an engine if it's going to turn above 4,000 RPM! (The factory maximum RPM for virtually all small gas engines, including all of Kohler engines is 3,600.) The high RPM or wide open throttle operation could cause them to break and destroy the engine! So when building an engine that's going to turn above 4,000 RPM, these gears (and spacers) MUST be permanently removed! Remember - "An ounce of prevention is worth a pound of cure." It's okay to leave the stub shafts in the block. Or if you want, the balance gear stub shafts can be removed with a hardened 7/16" steel rod and a big hammer to drive them out from the PTO end of the block. They will fall into the block. And don't worry about driving out the stub shafts with a hammer, the engine block will not crack. But using a hydraulic press to drive the pins out could cause the block to crack.

The easiest way to block off the stub shaft holes after removal is with 1/2" tapered expansion/cup plugs. Use silicone sealant to prevent an oil leak, too. Another way to block off the stub shaft holes to cut 3/8" NPT threads into the holes from outside the block, and then install a couple of 3/8" NPT Hex Socket (Allen) pipe plugs. Click or tap here if you need either these parts.

How To Remove the Crankshaft from a Kohler Engine -

Remove the piston/connecting rod, flywheel, bearing plate and anything that's on the PTO end of the crankshaft. (Not necessarily in this order.) Then very gently, bump the PTO end with a wooden block to remove the crankshaft from the block. And there's no need to reinstall the balance gears. They serve very little purpose.

FYI - A cast iron flywheel with a cooling fin (fan blade) broken off will definitely run out of balance, and cause the entire engine to vibrate badly. At higher RPM (up to 4,000 RPM), the excessive vibration could also cause the sheet metal to crack at the mounting bolt holes, and in rare cases, possibly cause the crankshaft to break at the rod journal. To statically (not spinning or in motion; at rest) put the flywheel back in balance, if the entire fin is broken off, simply break off the fin directly opposite of the broken fin with a hammer. But if only part of the fin is chipped off, use an angled hand grinder or a reciprocating saw / saw saw to remove about the same amount of chipped off material from the opposite fin. Try to make the fins match each other to maintain proper balance. The flywheel should still be safe to use, and the remaining intact fins will provide plenty of fresh air to adequately cool the engine. But the best way to put the flywheel 100% back in balance is to have it dynamically precision spin-balanced with an automotive crankshaft/flywheel balancing machine.

How Fast Can You Spin A Cast Iron Crankshaft?

As long as the piston assembly and connecting rod to the crankshaft counterweights, including the flywheel, starter pulley and clutch components are all precision balanced, you can spin it as fast as you want. Just make sure to have the crankshaft checked for stress cracks (magnafluxed) before using it.

When installing a high-performance [heavier than OEM stock] piston and connecting rod assembly in a single cylinder engine, and to minimize dangerous vibration and to prevent the possibility of self destruction, the crankshaft must be re-balanced (more weight added to the counterweights) to compensate for the difference in weight. If an engine vibrates excessively, then the only things that causes the vibration is the piston/rings/wrist pin/clips assembly and/or the connecting rod isn't equally balanced to the crankshaft's counterweights. Another thing would be an out of balance flywheel. Also, if there's a parasitic accessory attached to the crankshaft, such as a bent pulley, it could be causing the vibration.

Note: when using an OEM piston assembly and connecting rod, and if the rod journal (crank pin) on the crankshaft is reground for a smaller diameter bearing, that will not throw off the balance of the rotating assembly. Because the undersized rod bearing will take up the material that was removed from the crankshaft.

FYI - STATIC balancing is when parts are at rest, and DYNAMIC balancing is when parts are in motion. Dynamic balancing is a more precise way to balance anything that spins, but static balancing is a lower cost alternative... also proven very effective. An accurate and precision electronic digital scale that breaks at 1/10^th of an ounce (0.1 lb.) or 1 gram to static balance a crankshaft to the piston and connecting rod assembly will be needed. For an example of how much 1/10^th of an ounce is, a dime (10¢) weighs exactly 1/10^th of an ounce or 2.8 grams. But with a single cylinder engine, it will still vibrate slightly due to the side thrust of the counterweights on the crankshaft, which is unpreventable.

How to Static Balance a Single Cylinder Engine - A proven, ingenious and innovative concept by Brian Miller because nobody else mentions about doing this online.

Acquire a precision electronic digital scale as described above. An accurate and precision balance beam scale can be used to weigh the differences between the stock piston/rod assembly and the high performance piston/rod assembly. An electronic digital scale is more precise for balancing an engine than a mechanical one. But the higher the capacity of an electronic digital scale, the less precise it will be.
Use pencil, paper and arithmetic for this procedure, to make a note of the results.
Weigh the stock (preferably std size) piston, rings, pin, clips and connecting rod as a unit. Make a note of the total weight. Be sure the scale is on a flat, level surface. If it's not, an inaccurate reading will result. Weigh the piston, rings, wrist pin, clips and connecting rod that originally came with the crankshaft. If you don't have the original piston/rod assembly, here's the approximate weights for them: The OEM stock K301 piston assembly and rod weighs 29.1 ounces or 823 grams. And the stock OEM K321, K341 and K361 piston assembly and rods weighs 31.4 ounces or 891 grams.
Now weigh the high-performance/aftermarket piston, rings, pin, clips, connecting rod and bearing insert as a unit. Make a note of that weight.
Subtract the two above È weights and make a note of the difference.
Now weigh the crankshaft that was originally used with the stock OEM piston/rod assembly. Make a note of that weight. The average weight of a typical cast iron Kohler K301 crankshaft with a 1" diameter x 3" long PTO end is 151 oz. or 4,280 grams. And the average weight of a typical K321, K341 and K361 crankshaft with a 1-1/8" diameter x 3" long PTO end is 158.2 oz. or 4,485 grams. Remember that the weight of every crankshaft will vary a few ounces depending on the length and diameter of the PTO end, if the PTO end has a drilled and threaded bolt hole, or if the flywheel end has a 3/8" threaded bolt hole or a 5/8" or 3/4" diameter stud. (These numbers are for reference only.)
Add the difference in weight of the two piston/rod assemblies above È to the crankshaft counterweights. To add weight to the crankshaft, fill in the factory drilled holes with lead capped with steel that's held in place with a roll pin driven in crossways; bolt or weld an 1/8"± curved plate steel on the side of the counterweight next to the gear (make sure the balance plate and/or bolts clears the compression release mechanism on the camshaft, if equipped); or if the crankshaft needs a lot of weight, drill holes through the counterweight(s) and install tungsten steel (heaviest metal available) secured in place with beads of welding. Try to add an equal amount of weight to each counterweight so the crankshaft won't it be too heavy on either end. Not doing this may result in crankshaft breakage over time. And remember, crankshaft breakage could destroy other internal parts of an engine as well! It must be a high-quality welding job whenever any welding is done on a cast iron crankshaft! Remember, cast iron is porous and absorbs oil. This means the counterweights must be thoroughly heated with an acetylene torch or the crank placed in a special oven furnace and rotated it against large flames to burn the oil out of the metal, then it'll be good for welding.
Weigh the crankshaft again and subtract the difference from the result that was derived in step 4.
The added weight to the crankshaft should now reflect the difference in weight of the two piston/rod assemblies. If it doesn't, it's OK to grind off some weight from the counterweights.
That's it! The crankshaft and piston/connecting rod assembly are now statically balanced. On the average, about 160 grams or 5.64 ounces of weight is added to the counterweights on a Kohler crankshaft to precision balance it for a stock connecting rod and piston/rings assembly.

If a high-performance K301 piston assembly is going to be used in a Kohler engine, a K321, K341 or K361 crankshaft can be used instead for rebalancing. Less weight will need to be added to the counterweights because of the smaller and lighter weight K301 piston assembly.

By the way - Actually, it's best to have the rotating assembly precision and dynamically spin-balanced with a crankshaft balancing machine. Because just bolting on a weight to side of one of the counterweights without spinning the crankshaft to check the balance against it and the rod and piston assembly may add too much weight or not enough and the engine might still vibrate a lot. I've seen this happen several times.

Heavy metal (tungsten steel) and tools that's specifically made for crankshaft balancing can be purchased from GOODSON (http://www.goodson.com) Tools and Supplies for Engine Builders. (Request a catalog from them.)

The reason most [high dollar] billet steel crankshafts break at wide open throttle is because they were not dynamically and precision spin-balanced using a specialized crankshaft/flywheel balancing machine. This happens when the counterweights on the crankshaft weighs much more than the piston and connecting rod assembly. When out-of-balance, the crankshaft flexes a few thousandths of an inch at high RPM, which weakens the metal and causes fatigue cracks, eventually resulting in breakage. When a crankshaft breaks, it can destroy the camshaft and possibly the engine block. So it's very important that an aftermarket billet steel (and cast iron) crankshaft be dynamically and precision spin-balanced when the engine is ran at very high RPM. Most manufacturers of billet steel crankshafts do not dynamically and precision spin-balance them. They include counterweights on the crankshaft that's pre-weighed and matched to the weight of the piston and connecting rod assembly to be used with the crankshaft. The counterweights must weigh the same as the piston and connecting rod assembly, with the exception of the weight of the rod journal, which counter-weighs the counterweights. When rotating, the rod journal too, adds weight to the piston and connecting rod assembly. And the same balancing machine that's designed to balance automotive crankshafts and flywheels can be used to balance single cylinder Kohler (and other makes of small engines) crankshafts and flywheels. To balance a crankshaft with a specialized flywheel/crankshaft balancing machine, all that is needed is a bob-weight that clamps on the rod journal. The bob-weight simulates the weight of (and must weigh exactly the same as) the piston and connecting rod assembly that is going to be used with the crankshaft to be balanced. If the piston and connecting rod assembly and/or crankshaft is used with another piston and connecting rod assembly and/or crankshaft, the rotating assembly will be out-of-balance.

But then again, when excessively out of balance, a billet steel crankshaft will not always break. A billet connecting rod will break instead. This happens when the piston and rod assembly weighs much more than the counterweights on the crankshaft. What happens is, as the engine rotates at high RPM or at wide open throttle, the weight of the piston and connecting rod is sent upward a lot more than the counterweights are sent downward , resulting in two unequal opposing forces, and this places excessive strain on the connecting rod cap' bolts. Eventually, the upward force of the piston and rod will cause the bolts to stretch (the 4-bolt hex socket (Allen) head cap screws (bolts) in certain billet rods are more prone to stretching), which will cause the rod to knock, and the continuing stretching of the bolts will cause them to break, ultimately resulting in connecting rod breakage, which can destroy the entire engine block. So it'll be a good idea to definitely spend the extra time and money to have your rotating assembly dynamically and precision spin-balanced.

Click or tap here to see what can happen to an unaltered 9-1/2" diameter cast iron Kohler flywheel when spun well above 4,000 RPM.

If the engine still vibrates at high RPM or at wide open throttle after doing the above È, it's either because of the side thrust of the crankshaft counterweights (which is normal in single cylinder engines), or if the vibration is excessive, have the flywheel checked for precision balance and/or the clutch assembly trued up in a metal lathe. If you have a garden tractor with rubber motor mounts, these must replaced with solid metal motor mounts. If the crankshaft/piston/rod are balanced correctly and the flywheel is also balanced, and the tapers are clean, the crankshaft should last the life of the engine. Even when used in high-performance conditions.

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Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website.

High Quality Inductive Small Engine Tachometer/Hour Meter with Replaceable Battery. A tachometer is required for monitoring and/or setting the maximum speed of a small engine, which is normally 3,200 or 3,600 RPM (depending on type of carburetor), to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Very accurate, vibration-proof and weatherproof construction. Can be surface-mounted and secured with two screws to monitor engine RPM, or hand-held to set engine RPM. Large 3/8 inch LCD display. Works with magneto or battery-powered ignition systems by selecting engine type by programming S1 and S2 buttons. If tachometer does not turn on automatically as soon as engine starts, press and hold the two buttons at the same time. Instructions included. Reads up to 99,999 RPM. Hour meter reads up to 9999:59 hours/minutes. Programmable maintenance hour setting with service icon, a service reminder when to change oil or other maintenance. Can be manually reset to Zero hours. Easy installation: Single wire wraps around spark plug wire and secured with two supplied nylon zip-ties. No wire terminal connections required. Includes replaceable CR2450 battery. Dimensions: 2" wide x 1-3/4" depth x 3/4" height. $25.00 each, plus shipping & handling. Please let me know if you're interested in purchasing this item and I'll give you the total amount with shipping and payment options.

High Quality Digital Tachometer/Proximity Sensor Kits. A tachometer is required in setting the correct engine RPM, which is normally 3,200 or 3,600 RPM (depending on type of carburetor), to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Choice of a RED or BLUE numeric display. Will work with most small engines or multi-cylinder automotive engines, gas or diesel. Very accurate, vibration-proof and weatherproof construction. The great thing about this type of tachometer is that it needs no setup or programming. Displays accurate RPM as soon as the engine cranks over to start. Displays up to 9,999 RPM. Tachometer returns to zero [0000] when engine is shut down. Can be used for lawn & garden equipment or competition pulling engines. Designed to be permanently mounted to monitor engine RPM at all times. Tachometer can be in-dash or panel-mounted. This precision digital tachometer operates with external power and on the same principle as my flywheel- or crank-trigger ignition systems with a proximity sensor to detect the target, which can be a small ferrous steel screw or pin, or magnet in a rotating disc on the crankshaft or on/in flywheel. Operates totally independent of the ignition system, or can be used with crank trigger ignition with the same proximity sensor. Sensor is capable of powering this digital tachometer and crank-trigger ignition module at the same time, with the exception of using the Dynatek Dyna S or PerTronix Ignitor modules. This tachometer must be wired separately or wiring can be incorporated with my crank-trigger ignition system that use a proximity sensor. A sturdy metal bracket will need to be fabricated by customer to mount the sensor in close proximity of the detector/trigger target. Set air gap/clearance at .010"-.188". Tachometer works with 8-24 volts DC, proximity sensor works with 6-36 volts DC. Dimensions for mounting hole for tachometer: 3" wide x 1-17/32" wide. Tachometer measures 1" in depth. Dimensions of proximity sensor: 15/32" diameter threads x 1-3/8" thread length. Wiring Instructions: #1 wire on tachometer connects to BROWN wire on proximity sensor and ignition switch (12 volt power), #2 wire on tachometer connects to BLUE wire on proximity sensor and engine/chassis ground (which connects to the negative (–) battery post), and #5 wire on tachometer connects to BLACK wire on either proximity sensor listed below. Wires #3 and #4 connects to nothing. Wiring is the same for the hall effect and inductive proximity sensors. Certain proximity sensors have an LED (Light Emitting Diode), which flashes when in close proximity of target. If the proximity sensor is wired incorrectly, the LED will illuminate at all times. Click or tap here for YouTube videos to see how well this tachometer works.

Tachometer only. Use with virtually any Normally Open 3-wire hall effect, inductive, or cube-shape inductive proximity sensor (w/flywheel trigger ignition). $22.00 each, plus shipping & handling.
Complete Tachometer Kit with Hall Effect Proximity Sensor (dimensions listed below) and Locking Set Screw Collar w/Embedded Magnet. When ordering, please indicate diameter of crankshaft PTO end for locking collar. $47.00 each, plus shipping & handling.
Complete Tachometer Kit with Inductive Proximity Sensor (dimensions listed below). Senses the head of a small steel screw installed in a rotating locking set screw collar, disc or flywheel. $32.00 each, plus shipping & handling.

Hall Effect Proximity Sensor. Dimensions: 15/32" Diameter x 2-1/2" Length x 43" Cable Length . (Senses the South pole of a small magnet embedded in an aluminum rotating locking set screw collar, disc, or OEM magnet embedded in a flywheel.) $10.00 each, plus shipping & handling.
Inductive Proximity Sensor. Dimensions: 15/32" Diameter x 2-1/2" Length x 43" Cable Length Inductive Proximity Sensor. (Senses the head of a small steel screw in stalled in a rotating locking set screw collar, disc or flywheel.) $13.00 each, plus shipping & handling.

Aluminum Locking Set Screw Collar w/Embedded Trigger Magnet. Use with hall effect proximity sensors only. $15.00 each, plus shipping & handling.
Steel Locking Set Screw Collar w/Steel Trigger Screw Head. Use with inductive proximity sensors or magnetic pickup coils. $15.00 each, plus shipping & handling.
When ordering either locking collar listed above, please specify diameter of crankshaft PTO end or shaft it's to be mounted on. Most common Kohler crankshaft PTO end diameters are 1", 1-1/8", but 3/4", 1-1/4", 1-3/8", 1-7/16" and 1-1/2" are rare. Most billet steel crankshafts have a 1-1/2" diameter PTO end (raised shoulder). Other sizes available.

Solid Metal Motor Mount Kit for Cub Cadet "Quiet Line" Garden Tractors. An original, ingenious, innovative concept invention by Brian Miller, because I was the one who originally thought of, promoted and advertised the use of this product. Please accept no copycat products of this kind. (But I do appreciate them acknowledging my ingenuity and intelligence.) [Return to previous section] [Top of Page]
Details include:

Replace OEM rubber ISO-mounts with a set of solid metal motor mounts to prevent repeated and costly damage to the clutch components!
These custom-made solid motor mounts replaces deteriorated OEM "ISO" rubber engine mounts, which is usually associated with a damaged "flexible" 3-pin clutch drive plate and damaged clutch components. They are also a must for competition pulling! Fits IH Cub Cadet "Quiet Line" garden tractor models 482, 800, 1000, 1100, 1200, 1204, 1210, 1211, 1250, 1282, 1340, 1450 and 1650. If the engine in your tractor is mounted on angled cradles with rubber mounts between the cradles and tractor frame, then these are what your tractor need.
Direct replacement for OEM ISO-rubber mounts with no modifications to the tractor whatsoever. A thick flat washer fastens on top of the cradles with the solid mounts sandwiched between the cradles and tractor frame. Torque the bolts at 35 ft. lb. Can be easily removed if rubber mounts are desired instead.
For general lawn and garden use, heavy towing, pushing snow or competition pulling. A MUST for competition pulling (or even everyday use) because these stabilize the engine and entire clutch assembly to prevent excessive engine vibration at high RPM or at wide open throttle, which can destroy the flexible 3-pin clutch drive plate, clutch disc and driveshaft components. These solid motor mounts weigh about 1 lb.
Precision machined by A-1 Miller's so they set the engine crankshaft height at the correct alignment with the driveshaft.
FYI - Rubber motor mounts are intended for operator comfort due to engine vibration only. The rubber ISO-mounted engine tractors with solid motor mounts installed would feel and operate just like the tractors with a solid-mounted engine. Some people who installed these solid mounts use their tractor just to mow grass tell A-1 Miller's that the solid mounts don't cause their tractor to vibrate much at all, while others who have installed them said the vibration is unbearable. If the entire tractor vibrates excessively after these solid mounts are installed, then the rotating assembly in the engine (crankshaft/connecting rod/piston assembly) and/or flywheel is obviously excessively out of balance and needs to be precision spin-balanced by an automotive/race engine machine shop. Because the old Kohlers was balanced during the 1960's-70's with old fashioned and out-dated analog technology and equipment, which is not as precision with today's computerized balancing technology and equipment. The IH Cub Cadet engineers (and engineers of other various makes and models of garden tractors) obviously knew that older Kohler engines were out of balance and would vibrate, this is the only reason they installed rubber motor mounts in the "Quiet Line" tractors. So if you want, to minimize the vibration, either install a set of new OEM Cub Cadet ISO rubber mounts or have the rotating engine parts (crankshaft/piston/connecting rod and flywheel) dynamically and precision spin-balanced with up-to-date technology for a smoother running engine. Or you can return these solid mounts for a full refund, less shipping & handling. And by the way - the two factory-welded reinforcement bars between the cradles is used only on Cub Cadet garden tractor models 1204, 1210, 1211, 1282 and 1340 to prevent the mounting bolt holes in the aluminum oil pan from being stripped out. They are not required with a cast iron oil pan or with solid motor mounts. When in doubt, Heli-Coil stainless steel thread inserts can be installed in an aluminum oil pan to prevent the threads from being stripped out.
Solid Motor Mount Kit. Includes four solid mounts, four thick flat washers and four grade 8 bolts/nuts/lock washers. $40.00 per set, plus shipping & handling. Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website. | [Top of Page] [Return to Previous Section, Paragraph or Website]

Cub Cadet "Quiet Line" Engine Mounting Rubber Snubbers/Bumpers and Rubber ISO-Mounts. Fits Cub Cadet "Quiet Line" garden tractor models 482, 800, 1000, 1100, 1200, 1204, 1210, 1211, 1250, 1282, 1340, 1450 and 1650. All these models have a rubber ISO-mounted engine to reduce overall tractor vibration for operator comfort. The rubber ISO-mounts can be adapted for use on various other makes and models of small engine equipment to reduce engine vibration throughout the frame. [Return to Previous Section, Paragraph or Website]

Rubber Snubber/Bumper with Threaded Stud. Provides stabilization of the engine and proper alignment of the driveshaft from tension of the drive belt to the mower deck. OEM Cub Cadet part # IH-61510-C1. $21.75 each, plus shipping & handling.
Rubber ISO-mount kit. This kit replaces the mount only on one corner. Order four kits for a complete set. OEM Cub Cadet part # 759-3952. $33.60 per kit, plus shipping & handling.
Complete Rubber ISO-mount set. This kit replaces the mount only on one corner. Order four kits for a complete set. OEM Cub Cadet part # 759-3952 (x4). $134.40 per set of 4 kits, plus shipping & handling.

A-1 Miller's Crankshaft Machine Repair Service - (Added 2/3/21)

Drill and tap flywheel end of Kohler K-series crankshaft for installation of 3/8" bolt when threads on integrated 5/8" stud are damaged beyond rethreading or when 5/8" stud breaks off. No need to purchase another high-dollar, hard to find crankshaft. Precision work performed in large metal lathe. Hardware include: 3/8-24 UNF grade 8 bolt, split lock washer and 3/8" x 5/8" step washer adapter. $55.00 for labor and hardware.
Drill and tap PTO end of Kohler crankshaft for installation of 3/8" bolt to retain electric PTO clutch or billet starter pulley. Precision work performed in large metal lathe. Hardware include: 3/8" grade 8 bolt, split lock washer and extra thick flat washer. $45.00 for labor and hardware.
Drill and tap flywheel end of Kohler K-series crankshaft for installation of 5/8" threaded steel stud when threads on integrated 5/8" stud are damaged beyond rethreading or when 5/8" stud breaks off. No need to purchase another high-dollar, hard to find crankshaft. Precision work performed in large metal lathe. Hardware include: Installation of 5/8-18 UNF stud, self-locking flywheel retaining nut and extra thick flat washer. $75.00 for labor and hardware.

Flywheel Retaining Nuts for threaded stud on end of K-series and steel crankshafts. IMPORTANT: Apply thin coat of motor oil on threads of crankshaft before installing nut then torque each at 65 ft. lbs.

Plain Nut. 5/8-18 UNF threads. Apply medium strength liquid threadlocker on threads to prevent flywheel from possibly loosening. Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.00 each, plus shipping & handling.
OEM-Type Castle/Tapered Seat Self-Locking Nut. 5/8" diameter, fine thread (5/8-18 UNF). A-1 Miller's part. Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling.
All-Metal Self-Locking Nut. 5/8" diameter, fine thread (5/8-18 UNF). Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling.
Plain Nut. 3/4-16 UNF threads. Apply medium strength liquid threadlocker on threads to prevent flywheel from possibly loosening. Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.00 each, plus shipping & handling.
OEM-Type Castle/Tapered Seat Self-Locking Nut. 3/4" diameter, fine thread (3/4-16 UNF). A-1 Miller's part. Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling.
All-Metal Self-Locking Nut. 3/4" diameter, fine thread (3/4-16 UNF). Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling.

Flywheel Retaining Bolt and Washer Kit for 3/8" threaded hole in end of crankshaft. Includes: 3/8" grade 8 bolt, split lock washer and extra thick flat washer. Most of these parts discontinued from Kohler. IMPORTANT: Apply thin coat of motor oil in threads of crankshaft or on bolt then torque 40 ft. lb. High quality aftermarket. $5.00 each, plus shipping & handling. Starter Pulley Retaining Bolt/Washer Kit for PTO end of crankshaft. Includes: 3/8" or 7/16" grade 8 bolt, split lock washer and extra thick flat washer. Certain professional pulling associations/clubs require this in case starter pulley comes loose on crankshaft and become an airborne projectile, which can cause serious injury to a bystander or spectator. Please indicate if you need the kit for a 3/8" or 7/16" bolt. $5.00 per kit, plus shipping & handling.

Flywheel / Aluminum Hub Retaining Washers. A thick, wide washer is a must to secure flywheel and prevent clutch/driveshaft aluminum hub adapter breakage! Each made of steel and measures 1-1/4" o.d. x approximately 1/4" thick.

Washer w/13/32" hole. Must be used with aluminum hub that has a 3/8" hole.

A-1 Miller's part. $3.00 each, plus shipping & handling.
OEM Kohler part # 12 468 03-S. $3.40 each, plus shipping & handling.

Washer w/5/8" hole. To be used with aluminum hub that has a 5/8" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-104. $3.50 each, plus shipping & handling.
Washer w/3/4" hole. To be used with aluminum hub that has a 3/4" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-71. $3.50 each, plus shipping & handling.

Step Washer Adapter. Use this part to center the OEM Cub Cadet or OEM John Deere cast aluminum clutch hubs, or the billet aluminum clutch hub with a 5/8" hole to a crankshaft with the 3/8" bolt on Kohler later model K-series and all Magnum engines. Professionally machined by A-1 Miller's to fit inside factory cast aluminum hub adapters. A must to prevent excessive wobble/vibration and prevent hub breakage and/or driveshaft/clutch breakage. [Return To Previous Section, Paragraph or Website]

$30.00 each, plus shipping & handling.

OEM Kohler Aluminum Clutch Hub Adapters. Fits John Deere and all models of Cub Cadet garden tractors.

Hub adapter w/5/8" hole and pulley. Used and in excellent condition. No longer available from Kohler. OEM Kohler part # 41 071 01. $40.00 each, plus shipping & handling.
Hub adapter w/3/8" hole. Used and in excellent condition. No longer available from Kohler. OEM Kohler part # 52 071 02-S. $40.00 each, plus shipping & handling.
Hub adapter w/5/8" hole. Used and in excellent condition. $40.00 each, plus shipping & handling.
Hub adapter w/5/8" hole. New. OEM Kohler part # 41 071 03-S. $88.10 each, plus shipping & handling.

High Quality 8 Ball Main Crankshaft Radial Bearings. Fits Kohler K-series and Magnum cast iron block engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. Heat treated chrome steel (AISI 52100) for higher resistance and durability. Supports up to 17,000 RPM. Works excellent for general lawn and garden engines or high performance engines that run at high RPM or at wide open throttle. Bigger balls rotate freer and run cooler, which create less rolling resistance and friction than 12 ball bearings with smaller balls. Aftermarket bearing packed with fresh grease from the factory. Dimensions: 1.57" (40mm) I.D. x 3.54" O.D. (90mm) x .90" (23mm) width. See note below Ê. NOTE: If yours have more than .005" of play due to wear, or it feels rough or "rubbles" when rotated by hand with motor oil applied, then it should be replaced. FYI - All ball bearings have always been made to the metric dimensions. Where applicable, the US and import manufacturers try to make them close to the inch dimensions as possible.

Used and in excellent condition OEM Kohler bearing with very little to no wear. OEM Kohler part # 235376-S. $5.00 each, plus shipping & handling. (When available.)
New high quality aftermarket. Our part #150973. Replaces Kohler part # 235376-S. $22.00 each, plus shipping & handling.
New. OEM Kohler part # 235376-S. $116.55 each, plus shipping & handling.

How to Simply and Accurately Balance a Rotary Lawn Mower Blade -

First of all, a special, high dollar magnetic lawn mower blade balancing tool is not required to balance a rotary lawn mower blade. All that's needed is a simple screwdriver or a nail driven in the wall. After the blade is sharpened, place it on the shank of the screwdriver, hold it straight out, giggle the blade end to end on the screwdriver by hand, and if one end of the blade droops down, that's the heavy end and that end will need to be sharpened more to remove metal to lighten it so it will be equal to or weight the same as the other end. Or a nail driven in a wall could be used instead to balance a lawn mower blade. The only exception to using the screwdriver or nail is blades with a five spoke center hole. These blades are harder (or nearly impossible) to balance with a screwdriver or nail because one spoke isn't centered with the blade. The only option is to use the cone balancer as shown to the right ->.

Available Soon - Detailed Illustrated Plans on How to Construct a Professional Pull-Back Garden Tractor Pulling Sled and a Self-Propelled Garden Tractor/Small Wheel Mini Rod Pulling Sled (Weight Transfer Machines) - (Updated 7/16/24) [Top of Page]

FYI - I'm getting closer to completing my sled plans. But being I have lots of work to do in my shop, I work on designing my sled plans in my spare time. As soon as my plans with an inventory list of parts to use and with illustrations are perfected, I'll post the announcement in my websites. And as for prices of the pull-back sled and self-propelled sled plans, I'm not sure yet. Make me an offer and I'll consider it. And remember - Perfection takes time. If it's worth having, it's worth waiting for. It'll be money well spent. - Brian Miller If interested, please contact me below.

Quality-Built and Nice-Appearing Garden Tractor & Mini Rod Self-Propelled Tractor Pulling Sleds (Weight Transfer Machines) For Sale - (Updated 8/17/24) [Top of Page]

Sleds will be built as orders are placed. A minimum 50% deposit is required for all sled purchases. Buyer/purchaser can test sled with their pulling tractors or vehicles on our 200 ft. dirt track, and then can tow it on the road (like a trailer) or haul it on a large, sturdy trailer. Sleds are designed with style and made beautiful to admire, and painted metallic or color of your choice. Also, sleds are designed to start easy, pull smoothly and sure to stop with grouser bar. They will also have a safety release lever up front so when the weight box tops out and trips it, it will automatically disengage the clutch to prevent major damage to the drive mechanism for the weight box. And it will have another safety release lever at the rear in case the clutch (for the weight box) is engaged when backing up the sled. The self-propelled sleds will have a varible speed mechanical drive system with hydraulics to lower the two front steering wheels/tires, and the bigger sled will use hydraulics to bring the weight box back to its starting position. By the way - the self-propelled garden tractor pulling sled that I built in 1995 (and sold in 2021) is such an excellent design, I realized later that I made something very special when other people copied it. It's still in use today; click or tap photo of it to the right for a larger view.

Small size, pull-back (non-motorized) sled with open cabin, comfortable swivel seat and controls within easy reach for operator. For use with 1,050 lb. garden pulling tractors and up to 1,500 lb. small wheel (26-12.00x12 tires) mini rod pulling tractors. Length of sled: 12 ft. Total weight of sled fully loaded with weights: approximately 4,000 lb. $6,000.00 each.
Small size, self-propelled (motorized) sled with open cabin, windshield, comfortable swivel seat for operator comfort and controls within easy reach for operator. Twin cylinder air-cooled small engine and transmission will be positioned forward in sled with weight box drive transmission and clutch system positioned rearward of sled. For use with 1,050 lb. garden pulling tractors and up to 1,500 lb. small wheel (26-12.00x12 tires) mini rod pulling tractors. Length of sled: 16 ft. Total weight of sled fully loaded with weights: approximately 7,000 lb. $25,000.00 each.
Medium size, self-propelled (motorized) sled with enclosed air-conditioned cabin, comfortable swivel seat for operator comfort and controls within easy reach for operator. Automotive engine (Chevy V8 with glasspack mufflers) and transmissions will be positioned forward in sled with weight box drive transmission and clutch system positioned rearward of sled. For use with mini trucks, big wheel mini rods and antique/classic tractors. Length of sled: 25 ft. Total weight of sled fully loaded with weights: approximately 18,000 lb. $250,000.00 each.
Prices are subject to change without notice. If interested, please contact me below. And remember - Perfection takes time. If it's worth having, it's worth waiting for. It'll be money well spent.

To place an order, send your item(s) for repairing, and/or for customer service assistance, and FREE honest and accurate technical support, please contact: Brian Miller of A-1 Miller's Performance Enterprises, 12091 N Route B, Hallsville, MO (Missouri) 65255-9604 USA. Please call in your order or send an email with a list parts you need and your contact information. Phone: 1-573-881-7229 (cell; call, text or leave voicemail) or use Whatsapp. Please call Monday-Friday, 9am to 5pm, Central time zone, except holidays. If no answer, please try again later. (When speaking with Brian on the phone, please be patient and understanding because I stutter.) E-mail: pullingtractor@aol.com. Payment Options. A-1 Miller's shop is open to the public Monday-Friday, 9am to 5pm, Central time zone, with an appointment on weekends, except holidays. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's new shop (click image to the right) to personally purchase parts, or drop off and/or pick up your carburetor, clutch assembly, engine and/or parts, etc., for repairing and/or rebuilding. Or visit the address of our (old) shop mentioned above to drop off your engine, transmission, transaxle, garden tractor, small motorized vehicle, etc. We also custom build pulling tractors and other small vehicles. Please contact me before coming so I'll be at my shop waiting for your arrival. When you visit our shop, you will be dealing directly with the owner for the best customer service. 12091 N Route B, Hallsville, MO - Google Maps "The road to a [trusted] friend's house (or shop) is never long." Don't sacrifice quality workmanship for distance. [Return To Previous Paragraph, Section or Website]

By the way - As business is booming, we relocated our business at 12091 N. Route B, Hallsville, MO 65255 with a new, bigger, better, fully insulated, heated and air-conditioned building/shop (shouse) so we can provide many more professional services and high quality parts, and hire more reliable and knowledgeable help to have our customer's parts orders fulfilled sooner, parts repaired sooner and engine rebuilds performed promptly without a long delay. We will also offer custom welding fabrication jobs and other custom services. And we also provide pick up and delivery service and perform professional repairs for various small engines and lawn & garden equipment! Photos of our new building/shop are posted here! 12091 N Route B, Hallsville, MO - Google Maps

Payment Options, and We Ship to Canada and Worldwide
Item(s) in a package or cushioned envelope weighing less than 1 lb. is sent by US Postal Service Airmail Letter Post for a 4-7 days delivery. Packaged item(s) weighing over 1 lb. and up to 66 lb. is sent by US Postal Service Airmail Parcel Post for a 4-10 days delivery. I cannot use the US Postal Services' Flat Rate Priority Mail envelopes and boxes to ship outside U.S. territories. Item(s) weighing over 67 lbs. or more is sent by FedEx Ground or equivalent services. We try to keep our shipping cost to customers within reason. Therefore, we don't ship our products in a fancy-looking package with our company name and/or logo on it because most customers will just toss it in the trash after they remove the contents. And being there is no USPS tracking number outside the US, all I can do is make sure I write your address correctly on the customs form and on your package.

My websites are not set up to process orders and accept payments. Therefore, to place an order with me, please call either number above or send an email with a list of parts you need, with your name, complete and correct postal mailing address and phone number. For payment options, I accept cash (in person), USPS Postal Money Orders, cashier's checks, business checks, MasterCard, VISA, Discover, American Express (please add 2.5% to the total amount for the credit/debit card processor's surcharge). If paying with a credit/debit card, please call me at either number above. Or to make a payment to me through PayPal, please click this link: https://www.paypal.com. Or use Cash App (username: pullingtractor) or Venmo (username: Pullingtractor) to make a payment to me. And be sure to mention a description of what the payment is for with your full name, postal address, phone number and email address. I also accept payments through Western Union Money Transfer or MoneyGram Money Transfers. If sending a money order or cashier's check, please include a note in the envelope with your name, complete mailing address, phone number, email address and a description of what the payment is for. I'll make a note of your order when I have all your information, and I may have to order some of the parts on your list, which should take a few days to come in, but I will send everything to you as soon as I have the parts in stock after I receive your payment.

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Click or Tap Here to Visit Brian Miller's Small Engine Repair and Garden Tractor Pulling Tips and Tricks Websites	Click or Tap Here to Visit A-1 Miller's Performance Enterprises Professional Automotive Services and Tractor Pulling Sled Sales Website
Click or Tap Here to Visit A-1 Miller's Performance Enterprises Online Catalog of Kohler Engine Parts and Cub Cadet Garden Tractor Parts and Services Website	Click or Tap Here to Visit the Missouri Mini Truck & Mini Rod Pullers Association Website

Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website.
High Quality Inductive Small Engine Tachometer/Hour Meter with Replaceable Battery. A tachometer is required for monitoring and/or setting the maximum speed of a small engine, which is normally 3,200 or 3,600 RPM (depending on type of carburetor), to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Very accurate, vibration-proof and weatherproof construction. Can be surface-mounted and secured with two screws to monitor engine RPM, or hand-held to set engine RPM. Large 3/8 inch LCD display. Works with magneto or battery-powered ignition systems by selecting engine type by programming S1 and S2 buttons. If tachometer does not turn on automatically as soon as engine starts, press and hold the two buttons at the same time. Instructions included. Reads up to 99,999 RPM. Hour meter reads up to 9999:59 hours/minutes. Programmable maintenance hour setting with service icon, a service reminder when to change oil or other maintenance. Can be manually reset to Zero hours. Easy installation: Single wire wraps around spark plug wire and secured with two supplied nylon zip-ties. No wire terminal connections required. Includes replaceable CR2450 battery. Dimensions: 2" wide x 1-3/4" depth x 3/4" height. $25.00 each, plus shipping & handling. Please let me know if you're interested in purchasing this item and I'll give you the total amount with shipping and payment options. High Quality Digital Tachometer/Proximity Sensor Kits. A tachometer is required in setting the correct engine RPM, which is normally 3,200 or 3,600 RPM (depending on type of carburetor), to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Choice of a RED or BLUE numeric display. Will work with most small engines or multi-cylinder automotive engines, gas or diesel. Very accurate, vibration-proof and weatherproof construction. The great thing about this type of tachometer is that it needs no setup or programming. Displays accurate RPM as soon as the engine cranks over to start. Displays up to 9,999 RPM. Tachometer returns to zero [0000] when engine is shut down. Can be used for lawn & garden equipment or competition pulling engines. Designed to be permanently mounted to monitor engine RPM at all times. Tachometer can be in-dash or panel-mounted. This precision digital tachometer operates with external power and on the same principle as my flywheel- or crank-trigger ignition systems with a proximity sensor to detect the target, which can be a small ferrous steel screw or pin, or magnet in a rotating disc on the crankshaft or on/in flywheel. Operates totally independent of the ignition system, or can be used with crank trigger ignition with the same proximity sensor. Sensor is capable of powering this digital tachometer and crank-trigger ignition module at the same time, with the exception of using the Dynatek Dyna S or PerTronix Ignitor modules. This tachometer must be wired separately or wiring can be incorporated with my crank-trigger ignition system that use a proximity sensor. A sturdy metal bracket will need to be fabricated by customer to mount the sensor in close proximity of the detector/trigger target. Set air gap/clearance at .010"-.188". Tachometer works with 8-24 volts DC, proximity sensor works with 6-36 volts DC. Dimensions for mounting hole for tachometer: 3" wide x 1-17/32" wide. Tachometer measures 1" in depth. Dimensions of proximity sensor: 15/32" diameter threads x 1-3/8" thread length. Wiring Instructions: #1 wire on tachometer connects to BROWN wire on proximity sensor and ignition switch (12 volt power), #2 wire on tachometer connects to BLUE wire on proximity sensor and engine/chassis ground (which connects to the negative (–) battery post), and #5 wire on tachometer connects to BLACK wire on either proximity sensor listed below. Wires #3 and #4 connects to nothing. Wiring is the same for the hall effect and inductive proximity sensors. Certain proximity sensors have an LED (Light Emitting Diode), which flashes when in close proximity of target. If the proximity sensor is wired incorrectly, the LED will illuminate at all times. Click or tap here for YouTube videos to see how well this tachometer works. Tachometer only. Use with virtually any Normally Open 3-wire hall effect, inductive, or cube-shape inductive proximity sensor (w/flywheel trigger ignition). $22.00 each, plus shipping & handling. Complete Tachometer Kit with Hall Effect Proximity Sensor (dimensions listed below) and Locking Set Screw Collar w/Embedded Magnet. When ordering, please indicate diameter of crankshaft PTO end for locking collar. $47.00 each, plus shipping & handling. Complete Tachometer Kit with Inductive Proximity Sensor (dimensions listed below). Senses the head of a small steel screw installed in a rotating locking set screw collar, disc or flywheel. $32.00 each, plus shipping & handling. Hall Effect Proximity Sensor. Dimensions: 15/32" Diameter x 2-1/2" Length x 43" Cable Length . (Senses the South pole of a small magnet embedded in an aluminum rotating locking set screw collar, disc, or OEM magnet embedded in a flywheel.) $10.00 each, plus shipping & handling. Inductive Proximity Sensor. Dimensions: 15/32" Diameter x 2-1/2" Length x 43" Cable Length Inductive Proximity Sensor. (Senses the head of a small steel screw in stalled in a rotating locking set screw collar, disc or flywheel.) $13.00 each, plus shipping & handling. Aluminum Locking Set Screw Collar w/Embedded Trigger Magnet. Use with hall effect proximity sensors only. $15.00 each, plus shipping & handling. Steel Locking Set Screw Collar w/Steel Trigger Screw Head. Use with inductive proximity sensors or magnetic pickup coils. $15.00 each, plus shipping & handling. When ordering either locking collar listed above, please specify diameter of crankshaft PTO end or shaft it's to be mounted on. Most common Kohler crankshaft PTO end diameters are 1", 1-1/8", but 3/4", 1-1/4", 1-3/8", 1-7/16" and 1-1/2" are rare. Most billet steel crankshafts have a 1-1/2" diameter PTO end (raised shoulder). Other sizes available.
Solid Metal Motor Mount Kit for Cub Cadet "Quiet Line" Garden Tractors. An original, ingenious, innovative concept invention by Brian Miller, because I was the one who originally thought of, promoted and advertised the use of this product. Please accept no copycat products of this kind. (But I do appreciate them acknowledging my ingenuity and intelligence.) [Return to previous section] [Top of Page] Details include: Replace OEM rubber ISO-mounts with a set of solid metal motor mounts to prevent repeated and costly damage to the clutch components! These custom-made solid motor mounts replaces deteriorated OEM "ISO" rubber engine mounts, which is usually associated with a damaged "flexible" 3-pin clutch drive plate and damaged clutch components. They are also a must for competition pulling! Fits IH Cub Cadet "Quiet Line" garden tractor models 482, 800, 1000, 1100, 1200, 1204, 1210, 1211, 1250, 1282, 1340, 1450 and 1650. If the engine in your tractor is mounted on angled cradles with rubber mounts between the cradles and tractor frame, then these are what your tractor need. Direct replacement for OEM ISO-rubber mounts with no modifications to the tractor whatsoever. A thick flat washer fastens on top of the cradles with the solid mounts sandwiched between the cradles and tractor frame. Torque the bolts at 35 ft. lb. Can be easily removed if rubber mounts are desired instead. For general lawn and garden use, heavy towing, pushing snow or competition pulling. A MUST for competition pulling (or even everyday use) because these stabilize the engine and entire clutch assembly to prevent excessive engine vibration at high RPM or at wide open throttle, which can destroy the flexible 3-pin clutch drive plate, clutch disc and driveshaft components. These solid motor mounts weigh about 1 lb. Precision machined by A-1 Miller's so they set the engine crankshaft height at the correct alignment with the driveshaft. FYI - Rubber motor mounts are intended for operator comfort due to engine vibration only. The rubber ISO-mounted engine tractors with solid motor mounts installed would feel and operate just like the tractors with a solid-mounted engine. Some people who installed these solid mounts use their tractor just to mow grass tell A-1 Miller's that the solid mounts don't cause their tractor to vibrate much at all, while others who have installed them said the vibration is unbearable. If the entire tractor vibrates excessively after these solid mounts are installed, then the rotating assembly in the engine (crankshaft/connecting rod/piston assembly) and/or flywheel is obviously excessively out of balance and needs to be precision spin-balanced by an automotive/race engine machine shop. Because the old Kohlers was balanced during the 1960's-70's with old fashioned and out-dated analog technology and equipment, which is not as precision with today's computerized balancing technology and equipment. The IH Cub Cadet engineers (and engineers of other various makes and models of garden tractors) obviously knew that older Kohler engines were out of balance and would vibrate, this is the only reason they installed rubber motor mounts in the "Quiet Line" tractors. So if you want, to minimize the vibration, either install a set of new OEM Cub Cadet ISO rubber mounts or have the rotating engine parts (crankshaft/piston/connecting rod and flywheel) dynamically and precision spin-balanced with up-to-date technology for a smoother running engine. Or you can return these solid mounts for a full refund, less shipping & handling. And by the way - the two factory-welded reinforcement bars between the cradles is used only on Cub Cadet garden tractor models 1204, 1210, 1211, 1282 and 1340 to prevent the mounting bolt holes in the aluminum oil pan from being stripped out. They are not required with a cast iron oil pan or with solid motor mounts. When in doubt, Heli-Coil stainless steel thread inserts can be installed in an aluminum oil pan to prevent the threads from being stripped out. *Solid Motor Mount Kit. Includes four solid mounts, four thick flat washers and four grade 8 bolts/nuts/lock washers.* $40.00 per set, plus shipping & handling.** Click here to contact A-1 Miller's Performance Enterprises to place an order, send your parts for repairing, and/or for FREE professional and honest technical customer service assistance and support and payment options. Please contact A-1 Miller's if you need a part or parts, or service(s) performed that's not listed or mentioned in this website. \| [Top of Page] [Return to Previous Section, Paragraph or Website]
Cub Cadet "Quiet Line" Engine Mounting Rubber Snubbers/Bumpers and Rubber ISO-Mounts. Fits Cub Cadet "Quiet Line" garden tractor models 482, 800, 1000, 1100, 1200, 1204, 1210, 1211, 1250, 1282, 1340, 1450 and 1650. All these models have a rubber ISO-mounted engine to reduce overall tractor vibration for operator comfort. The rubber ISO-mounts can be adapted for use on various other makes and models of small engine equipment to reduce engine vibration throughout the frame. [Return to Previous Section, Paragraph or Website] Rubber Snubber/Bumper with Threaded Stud. Provides stabilization of the engine and proper alignment of the driveshaft from tension of the drive belt to the mower deck. OEM Cub Cadet part # IH-61510-C1. $21.75 each, plus shipping & handling. Rubber ISO-mount kit. This kit replaces the mount only on one corner. Order four kits for a complete set. OEM Cub Cadet part # 759-3952. $33.60 per kit, plus shipping & handling. Complete Rubber ISO-mount set. This kit replaces the mount only on one corner. Order four kits for a complete set. OEM Cub Cadet part # 759-3952 (x4). $134.40 per set of 4 kits, plus shipping & handling.
A-1 Miller's Crankshaft Machine Repair Service - (Added 2/3/21) Drill and tap flywheel end of Kohler K-series crankshaft for installation of 3/8" bolt when threads on integrated 5/8" stud are damaged beyond rethreading or when 5/8" stud breaks off. No need to purchase another high-dollar, hard to find crankshaft. Precision work performed in large metal lathe. Hardware include: 3/8-24 UNF grade 8 bolt, split lock washer and 3/8" x 5/8" step washer adapter. $55.00 for labor and hardware. Drill and tap PTO end of Kohler crankshaft for installation of 3/8" bolt to retain electric PTO clutch or billet starter pulley. Precision work performed in large metal lathe. Hardware include: 3/8" grade 8 bolt, split lock washer and extra thick flat washer. $45.00 for labor and hardware. Drill and tap flywheel end of Kohler K-series crankshaft for installation of 5/8" threaded steel stud when threads on integrated 5/8" stud are damaged beyond rethreading or when 5/8" stud breaks off. No need to purchase another high-dollar, hard to find crankshaft. Precision work performed in large metal lathe. Hardware include: Installation of 5/8-18 UNF stud, self-locking flywheel retaining nut and extra thick flat washer. $75.00 for labor and hardware.
Flywheel Retaining Nuts for threaded stud on end of K-series and steel crankshafts. IMPORTANT: Apply thin coat of motor oil on threads of crankshaft before installing nut then torque each at 65 ft. lbs. Plain Nut. 5/8-18 UNF threads. Apply medium strength liquid threadlocker on threads to prevent flywheel from possibly loosening. Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.00 each, plus shipping & handling. OEM-Type Castle/Tapered Seat Self-Locking Nut. 5/8" diameter, fine thread (5/8-18 UNF). A-1 Miller's part. Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling. All-Metal Self-Locking Nut. 5/8" diameter, fine thread (5/8-18 UNF). Replaces Kohler part #'s 25 100 02-S, X-119-14. (Discontinued from Kohler.) $1.50 each, plus shipping & handling. Plain Nut. 3/4-16 UNF threads. Apply medium strength liquid threadlocker on threads to prevent flywheel from possibly loosening. Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.00 each, plus shipping & handling. OEM-Type Castle/Tapered Seat Self-Locking Nut. 3/4" diameter, fine thread (3/4-16 UNF). A-1 Miller's part. Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling. All-Metal Self-Locking Nut. 3/4" diameter, fine thread (3/4-16 UNF). Replaces Kohler part #'s X-89-11, X-119-16. (Discontinued from Kohler.) $1.75 each, plus shipping & handling.
Flywheel Retaining Bolt and Washer Kit for 3/8" threaded hole in end of crankshaft. Includes: 3/8" grade 8 bolt, split lock washer and extra thick flat washer. Most of these parts discontinued from Kohler. IMPORTANT: Apply thin coat of motor oil in threads of crankshaft or on bolt then torque 40 ft. lb. High quality aftermarket. $5.00 each, plus shipping & handling.	Starter Pulley Retaining Bolt/Washer Kit for PTO end of crankshaft. Includes: 3/8" or 7/16" grade 8 bolt, split lock washer and extra thick flat washer. Certain professional pulling associations/clubs require this in case starter pulley comes loose on crankshaft and become an airborne projectile, which can cause serious injury to a bystander or spectator. Please indicate if you need the kit for a 3/8" or 7/16" bolt. $5.00 per kit, plus shipping & handling.
Flywheel / Aluminum Hub Retaining Washers. A thick, wide washer is a must to secure flywheel and prevent clutch/driveshaft aluminum hub adapter breakage! Each made of steel and measures 1-1/4" o.d. x approximately 1/4" thick. Washer w/13/32" hole. Must be used with aluminum hub that has a 3/8" hole. A-1 Miller's part. $3.00 each, plus shipping & handling. OEM Kohler part # 12 468 03-S. $3.40 each, plus shipping & handling. Washer w/5/8" hole. To be used with aluminum hub that has a 5/8" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-104. $3.50 each, plus shipping & handling. Washer w/3/4" hole. To be used with aluminum hub that has a 3/4" hole. A-1 Miller part. (Discontinued from Kohler.) Replaces Kohler part # X-25-71. $3.50 each, plus shipping & handling.
Step Washer Adapter. Use this part to center the OEM Cub Cadet or OEM John Deere cast aluminum clutch hubs, or the billet aluminum clutch hub with a 5/8" hole to a crankshaft with the 3/8" bolt on Kohler later model K-series and all Magnum engines. Professionally machined by A-1 Miller's to fit inside factory cast aluminum hub adapters. A must to prevent excessive wobble/vibration and prevent hub breakage and/or driveshaft/clutch breakage. [Return To Previous Section, Paragraph or Website] $30.00 each, plus shipping & handling.
OEM Kohler Aluminum Clutch Hub Adapters. Fits John Deere and all models of Cub Cadet garden tractors. Hub adapter w/5/8" hole and pulley. Used and in excellent condition. No longer available from Kohler. OEM Kohler part # 41 071 01. $40.00 each, plus shipping & handling. Hub adapter w/3/8" hole. Used and in excellent condition. No longer available from Kohler. OEM Kohler part # 52 071 02-S. $40.00 each, plus shipping & handling. Hub adapter w/5/8" hole. Used and in excellent condition. $40.00 each, plus shipping & handling. Hub adapter w/5/8" hole. New. OEM Kohler part # 41 071 03-S. $88.10 each, plus shipping & handling.
High Quality 8 Ball Main Crankshaft Radial Bearings. Fits Kohler K-series and Magnum cast iron block engine models K241, M10, K301, M12, K321, M14, K341, M16 and K361. Heat treated chrome steel (AISI 52100) for higher resistance and durability. Supports up to 17,000 RPM. Works excellent for general lawn and garden engines or high performance engines that run at high RPM or at wide open throttle. Bigger balls rotate freer and run cooler, which create less rolling resistance and friction than 12 ball bearings with smaller balls. Aftermarket bearing packed with fresh grease from the factory. Dimensions: 1.57" (40mm) I.D. x 3.54" O.D. (90mm) x .90" (23mm) width. See note below Ê. NOTE: If yours have more than .005" of play due to wear, or it feels rough or "rubbles" when rotated by hand with motor oil applied, then it should be replaced. FYI - All ball bearings have always been made to the metric dimensions. Where applicable, the US and import manufacturers try to make them close to the inch dimensions as possible. Used and in excellent condition OEM Kohler bearing with very little to no wear. OEM Kohler part # 235376-S. $5.00 each, plus shipping & handling. (When available.) New high quality aftermarket. Our part #150973. Replaces Kohler part # 235376-S. $22.00 each, plus shipping & handling. New. OEM Kohler part # 235376-S. $116.55 each, plus shipping & handling.