Trying to repair my centrifugal clutch



Any idea where I can get this piece? It just broke today, and until I get this part, the bike will be sitting in the garage. Please let me know if you have one or know where to get one. (It's the center post for the one-way bearing in the centrifugal clutch)

*****Scroll down for much better photos that were added on 2/3/07*****

Here is a photo of the entire assembly:



I cannot believe how incredibly difficult it is to get a part for this clutch. Plenty of places sell motor kits with a centrifugal clutch, but nobody has any parts available for them.

This is turning out to be about as bad as trying to get the Hall Sensors to fix my electric bike, which I eventually had to find myself by searching through piles of semiconductor spec sheets.

So far I have contacted all of the following vendors and none of them could get me the part based on the photo from the first post:

Simpson Motorbikes
Live Fast Motors
Kings Motorbikes
Five Flags Motorbikes
the eBay vendor I bought it from, along with several other eBay vendors
Dennis Foster (who is actually still looking based on the new photos I took)

Here is the worst response I got so far:
>Sorry, our kits don't have centrifical clutches. We would love to earn
>your business on one of our new bike engine kits. They have a 100%
>reliability rate so you won' t have to worry about parts and repair.

Beautiful. They don't sell parts because it is impossible for their motors to break or wear out. I wonder where they are getting those magic motors.


One last try to find clutch parts

I took new photos of the broken part on my bike today. I posted photos which detail the mounting location of the part, other parts it is attached to, closeups of the part, and how the part looks when it is attached to the motor or the rest of the clutch. This should leave no room at all for any confusion as to what I am looking for.

If ANYBODY has ANY information on a possible part number/vendor for this part, please let me know, as my bike will not run without it.

So far, only one vendor has mentioned availability. He said he can sell me the entire clutch kit for $40. I agreed, but then he told me he didn't have any.

Here are the photos that explain what I am looking for in order to get my bike running again:



Not a bad idea. Do you know how much something like that might cost?

By the way, after I posted the new photos, Dennis said he might be able to find me one (he should know by tomorrow).


Active Member
Nov 4, 2006
Blaze said:
Not a bad idea. Do you know how much something like that might cost?

By the way, after I posted the new photos, Dennis said he might be able to find me one (he should know by tomorrow).
I feel your pain. s*cks to have cool toys ya can't play with.

We have some machinests among us. maybe someone can give you a ballpark quote on cost of your part.

Also, I believe the centrifugal clutch model is the only legal kit on Canada's roadways. Any Canadian dealers out there?

on a lighter note....I am sure glad you found the New 100% reliable, never needs parts or repair, Virtual Engine!
we'll all sleep better now! :lol:

good luck, Blaze & keep us posted.


You might try a chainsaw repair shop( the older and larger the better) for a complete clutch assembly. I wouldn't expect them to have the damaged part, but maybe a complete clutch assembly that could be substituted. The damaged part pictured looks easy to machine.


I went to a machine shop today. I was quoted about $175 to make the part. That's about what the entire kit costs for an engine with a centrifugal clutch.

Looks like I have 2 options left. One is the guy I bought the kit from who says he can get me an entire clutch set for $40 in about a month or so. The other is Dennis Foster, who was too busy to look through his parts last week, so hopefully he can have a look through them this week. He is supposed to get back to me this weekend to let me know if he has anything.

john new cumberland

broken clutch bushing

You could try silver soldering it, or making another out of a piece of pipe, welding a washer on one end, tapping the threads, and filing the flats. Probably the most important thing is why it broke. The bolt must have come loose. This could have been prevented with loctite if it doesn't get too hot. If it is chronically hot the only way to get it to stick might be to ding the threads on the bolt.


I just bought a spare parts motor from the same guy I have been buying all of my motor kits from. He was going to sell me the clutch kit for $40 (which is less than half of what it cost from Grubee), but the wait time was a couple months. He offered me a spare motor for $80 and I took it. It a kind of complete motor, with a cylinder and piston that was a different size than mine, but a head that was the same size. The bottom end all matched up. Now I have plenty of spare parts.

The problem was from the bolt coming loose, and I agree with you completely about the Loctite (which is on the new assembly I installed). This was the first motorized I ever built, and I had to do it without this forum, so I was pretty much working blind. I now keep blue and red loctite in my toolbox, and I use it liberally (mostly red). The red loctite will have no problem with the temperatures the clutch deals with.


You probably solved the problem now, but the idea may be useful to another person.
I think that piece may be replaced with a needle bearing (i attach some picture, to give you some idea).
I have a very old version of the same engine, quite primitive, and it runs his clutch in oil. It has a needle bearing between the bell and the crank shaft.
(i put some pictures of the entire disassemble).



Hot Dog Piggy Tails

My new one is Similar

The darned needle bearing must be out on it cause it sounds like metal on metal scraping coming from in there or my lower end musta been stored outside or something.


New Member
Jun 4, 2010
Rehashing super-old thread

Rehashing a super-old thread, sorry about that..
I have a centrifugal clutch with a bearing that cracked in the same was as the OP's.
I just ground a channel on the inside surface of the bearing (where the crankshaft goes) over where the cracks are, It looks kinda like a keyway, with the cracks above it, dumped some weld into the channels and ground the inside back to the correct size.
That solved the problem for me.


Well-Known Member
May 17, 2010
im in agreement with the silver solder statement.

if it can hold carbide onto a drill bit that gets slammed into rock 24/7, it can hold a cracked bush together.

or braze it, slightly hotter, more chance of distortion, but also slightly harder. bronze welding has been around for a looooong time.

whichever machine shop tried charging you $175 was the wrong machine shop!!!

guy down the road would charge me...nothing, but id give him 20 anyway.

but now i have my own tools... id make one for maybe $5... gee, its hard! drill, tap. feed bar. turn to OD, with two shoulders. part off. clamp in mill and run cutter across smaller shoulder to give the "D" shape.

want it hardened? $10 cus id have to order 4140 or similar, and then fire up the forge... possibly finish grind to size.