Clutch Slip When Cold

[D. P. Larmee]

This winter I started noticing that when the outside temps are below 30* or so my clutch will start to slip if i'm in fifth and grab a little too much throttle. It seems to go away as the temps climb. As I've not seen this in past winters, I can only assume that it won't be long untill it starts slipping when it's warm out too. Then again, this is the first winter with vetter with lowers, so it is probably safe to assume that in previous winters, I wasn't doing much high speed riding in below freezing temps. Just wondering if my clutch is on its way out or if this is relatively normal in the cold weather. I have had past issues with the starter clutch in the cold, I didn't know if this is a similar issue. The clutch is adjusted per the manual and I'm running the same type of good old dino juice that I've always used, although I did switch to 10w30 for the winter.

Dan

[stoked]

It's more than likely your clutch springs. They get soft after years of service. I had exact same symptons and after reading quite a few posts on the subject I decided to spend the 15 bucks with shipping on some I belive EBC springs from bike bandit. Replacing clutch springs is only slightly more difficult than changing spark plugs on this bike. So after 30 minutes of labor my slipping clutch issues are now resolved.

[xschop]

just like donuts

your plates are begining to GLAZE......baby it till you are ready to take the whole basket out, if they are within spec (thickness), you can clean/sandpaper them like new....20% sodium hydroxide works a miracle, or you can use easy-off oven cleaner

[webbcraft2150]

I would try new springs before diving into the clutch. I put a new clutch in my 80g at 67k on the clock. I had new fibers on hand, ALL the old ones were still well within specs as were the steels. You can R&R springs real easy. Need a case gasket and MUST read tech tip on reinstalling the "star". Do it wrong and you will be trying to find one, they will snap real easy. Don't glue the case gasket to the engine and you can save it if you find later you do need to get into the whole clutch.

[D. P. Larmee]

Thanks guys. That's what I figured. I'll order new springs and a gasket and see if that solves the problem. I only have around 30,000 on the bike so I would be real surprised if the plates were out of spec. If the springs don't do it, I'll move on to the plates. I just wanted to check with you all to make sure that this wasn't a common issue with these clutches when cold.

[red bandit]

If you put a "LIGHT" film (don't glob it on) of grease engine case the next time you pull the side cover the gasket won't stick to case. After that, reuse gasket and put a "LIGHT" film of grease on case, no leaky.

[mro]

The "extra steel" mod works very well too.


mro

[D. P. Larmee]

Would you recommend the extra steel in place of new springs or in addition to?

[mro]

in addition to?

You can measure your springs to see if the length is still in spec., but need a scale to check to see if they have lost some stiffness.

Best to pull clutch. Measure plates. Plates still in spec. would add the extra steel and put in a set of the "heavy duty" springs.
Think they only cost $8 to $12 per set and are about 10% stiffer.
Will notice this in left hand for a few days then will seem normal.
The barnett springs (to me) seem to be best, but the ones I put in the 80G worked well too.


mro

[stoked]

It's suprising how much of a difference a little bit of stiffness can make. The old springs didn't seem to much softer than the new ones to me. That was using my calibrated thumb and index finger. They were a mm or so shorter than the new ones though. But again that wouldn't seem odd to me since most valve springs I've messed with have had very different spring heights and ratings in the same application. But the new springs made all the difference in the world. I went from pretty bad slipage in 3rd through 5th under load to absolutely none at all no matter what I try in any gear.

But I would replace the springs for sure due to their very fundamental part the design of the way a clutch works. Their spring rates may be variying greatly between each spring. And why add the extra steel if you don't need it. If the new springs don't hold it then I'd consider that. But wouldn't the extra steel just be more wear on your new springs. Maybe not enough to matter but I'm just thinking out loud.

[D. P. Larmee]

Yea, that's kind of what I was thinking. That if the extra steel wasn't needed, that it could cause premature wear on the springs. Has anyone found a reliable way to measure the wear on the pressure plates to see if there is a true need to shim the springs or add an additional steel? I'm sure that in many cases there is a legitimate need, but I'm not sure how to tell definitively whether or not there is.

[TopCatGr58]

Hey DP,

I had put new frictions and HD springs in mine when I did my rebuild back in 2001, but it started slipping on me last year! When I tore into it, my frictions were almost to full spec, the springs were already SPRUNG! I had read about wear on the main pressure plates (aluminum) that could contribute to the overall loss of compression of the disc pack, and so that's why I opted for the extra steel along with new springs, and I had new frictions so I put them in anyways! I'll use the almost new frictions in another bike I have, along with new springs. The extra steel is essentially the same as shimming the springs, but I think a bit safer vs. washers under the springs...have heard of folks breaking the star plate or the pressure plate bolt stalk from putting the washer in the wrong place!
T.C.

[skids]

I was one of those guys that broke a star plate. The posts for the springs fit against the star plate in a counter-sunk configuration. If you put washers on THAT end, it causes the washers to bend into a crescent shape and causing the tip of the star plate to snap off! What was I thinking!???

[D. P. Larmee]

That's why I love this place. The most knowledgeable people you'll find anywhere and a willingness to share that knowledge. You guys have tips and tricks to make just about any procedure go that much smoother. Thanks again.

[79XS11F]

Start with the simplest things first like cable adjustment "when cold" because if you do it when hot the cable will be tight when cold. Check the under cover adjustment as well. If cable and under cover are good then start looking at the clutch itself.
Rob