Clutch Material and Inner Spring

So the clutch is slipping on the 66cc china girl. This is all that I have tried.

All the clutch parts have been cleaned with brake cleaner, pads and pressure plate dressed down with sand paper to remove the glaze.

Adjusting the flower nut didn't help, the only effect it had was were the position on the clutch arm with the cluch was released.

Inner spring- No matter how tight I tighten it clutch still slips. I tightened it 1/2 turn at a time untill it was to the point that the spring was completely compressed. I left the cable dissconected during the test. Tried adjusting flower nut at each test. As previously stated it still slipped.


So I think I'm down to replacing the pads and/or inner spring. I want to find some stronger than what it came with. I've read that some have had luck with mcmaster but they don't mention what type of material they used, I saw five differnt types on their site. I've also read that some have suggested automotive valve springs, has anyone ever tried it? What lb spring was used?

Any help appreciated, thanks

dodge dude94 said:

That little inner spring there is only used to keep the flywheel from rattling around so badly. It has no effect on clutch operation.
If it's still slipping after tightening down the flower nut you need new pads. How many miles do you have on them?


I've read something on here around some pads that are red, I think they're a higher temperature compound that is stickier than the stockers.

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As far as I know, the little spring under the pressure plate is known as the outer spring, and the one that actually inguages the clutch is called the inner spring. Norman and a couple others made how-to threads on the procedure to tighten the inner.

Norman's thread
http://motorbicycling.com/showthread.php?t=8392

reg454's thread
http://motorbicycling.com/showthread.php?t=8739

Thanks for the tip on the reds. From what I've read about them their better than the older black ones like I got, but still far from great.

Keep the tips coming...

crassius said:

I'm assuming that by 'inner spring' you're referring to the spring under the cable mount. Having tightened that, you're about as tight as you're going to get, so there are only two things it could be.

a) Pads are very worn or pads are not going all the way thru their slots to make good contact with rear plate. For this, replace pads or trim pads for good movement thru slots.

b) Pressure plate is not pushing properly on pads. For this, check that flower nut has not sunk down far enough to bind on the end of the shaft (look for scaring near end of threads), also, look for deformity of the plate itself (sometimes the outward dimple needs to be hit with a ball-peen hammer hard enough to bell it out a bit more).

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I've tried trimming the pads, forgot to list in in the first post (oopps )
I'll have to check that flower nut.

The clutch grips well enough to start but slips a little when doing so. Also slips a little during hard accelerations. All that slipping uses up clutch pads, so I have to adjust it every few miles or else it will wear off enough that it starts slipping all the time.

flower nut looks ok. In my previous search of this forum I found this thread in which a member made cluch pucks from material from mcmaster-carr, but they don't say which material was used.

http://motorbicycling.com/showthread.php?t=39346


The pic on that thread shows it in a sheet. Mcmaster sells low, medium, and high density in the sheets. From the pic it almost looks like low density, what do you guys think?

http://www.mcmaster.com/#brake-lining/=ms77d4

biknut said:

99.9999% chance this is what the problem is. It's your clutch pads. They're binding in the clutch gear, and only making good contact on one side of the pressure plate.

What you need to do is remove all the pads. Take a flat bastard and file the edges of the pads until they easily fit into the square holes in the clutch gear.

Even if you buy new clutch pads, you still need to do this.

Click to expand...

I've tried that, didn't help. They can be removed and installed easily with one's finger.

midwestmayhem said:

I've tried trimming the pads, forgot to list in in the first post (oopps )

Click to expand...

The clutch worked fine when the motor was new, it only started sliping reciently.

I tried adjusting the flower nut again this morning. I tightened it a bit, and pulled the clutch lever. I immediatly noticed a harder pull, but before I was able to pull it far enough to disengage the clutch I heard a pop from inside the motor. After that the clutch was soft again. I think the inner spring adjustment might have stripped? Could be the reason it started slipping in the first place?

Update- The ferrule broke right were the pintle goes through. Looks as if the metal on the side of the hole in the ferrule for the pintle wore thin and couldn't hold anymore. Clutch doesn't work at all now.



Ordered a complete new assembled clutch shaft, I'll keep you all informed