Cleaning clutches

I like to use a slightly different amount of grease on my clutches (much, much less). I also take apart regularly to check for uneven wear. I don't believe the backing plate on Bully (and Horstman) were ever intended on being removed, hence the stripped out allens.

Buller has a good info sheet that includes maintenance that is reasonable for any disk clutch.
Brake clean will not clean disks can prove it to yourself by disassembling clutch and clean disks with brake clean ...lacquer thinner whatever you want and after you are happy with them lay them on a piece of white paper and take a small brass bristle brush and go over disks ...and see all the black that will be laying on the paper make a small pile of black and dip your finger in the black stuff and rub it between your fingers and feel how slick it is it will feel like graphite lube something I don't want on my clutch ... definitely a big difference on lock up after you get in the habit of doing your clutches like this ! You could also just take a disk you have laying around to test this before you believe


What is the best way to clean a bully clutch?
Straight from the bully instructions

I also manipulate the disks while basket is off to expose as much of the surface as possible and hit the them with a brass wire brush to loosen up grit and dirt before following these instructions.

I run Bully clutches on my kids JR1 & JR3 karts and this hasn’t failed me yet. I do like the SMC Viper clutches as they as really easy to take down and clean but don’t seem to work as well as the Bully for the kids.


The clutch should be protected from moisture and dirt as much as possible. It is important that a small amount of lubrication is provided to the chain. However, too much lubrication can cause the lubricant to migrate to the friction disks and render them useless. So, oil the chain sparingly. The clutch should be cleaned after each race night. To clean your clutch we recommend taking the sprocket/ basket assembly off the clutch. Take the 2 pieces and soak them in a bath of acetone for about 10 minutes. After soaking, spray the clutch out with air, re-lube the sprocket bearing with a small amount of Vaseline and reinstall on the motor. Periodically the air gap and disc thickness should be checked but we do not recommend disassembling the clutch except to change the air gap or rebuild the clutch.

The thrust bearing located in between the sprocket and the clutch hub should be run dry. Of course its life would be extended by lubricating it, but the lubrication from this bearing is most likely to contaminate the friction discs. Since the price of replacing the thrust bearing is very low compared to the price of friction discs, we recommend that this bearing be run dry. The friction disks should be replaced when their thickness becomes less than .110” or when the square outer drive prongs become deformed. A chatter condition in the clutch will cause almost immediate damage to the friction disk drive prongs and the basket.

The pressure plate and the clutch hub should periodically be checked for warpage and straightness. If in doubt, they should be re-ground or replaced.

Levers require visual inspection each time the clutch is disassembled. Look for flat spots developing on the nose of the lever. By the nose, we are referring to where the lever contacts the pressure plate. If any noticeable wear is seen, the lever should be replaced. Also make sure that the lever is able to rotate freely on the dowel pin.