Clutch Sticking and Slipping - Please advise

[ssaulnier]

I got my 2 sons into dirt biking January 1st 2008 and we have been having a great time since. We ride the trails on the San Antonio Dirt Bike Club lease.

I got a nice used RM125 for my older boy (15) and an RM85 for the 11 year old. It is hard to find neutral on both bikes because the clutch drags just a bit.

The 125 clutch also slips when I wind it out in 5th or 6th gear (making max power and hauling my 210 lbs).

Adjustments don't help. If I reduce the drag then the clutches slip. I have taken both clutches apart and they look almost new. The clutch baskets and plates are not worn and the transmission shift detent and springs look fine.

I am presently running the correct weight motor oil in the gearboxs recommended in the manuals. I wonder if ATF will help the dragging problem?

I also got some new clutch springs for the 125 to try and fix the slipping problem since it is a 1991 and those springs have to be getting a bit weak. I have not put them in yet. Too many business trips this month. :(

Any other recommendations? Thanks, Steve

 

[mudpack]

Pull the clutch plates, both the steel and the fiber ones. Don't just look at them, measure them!
They may look fine, but might be out-of-flat (causing drag) and worn too thin (causing slippage). These are not things you can see with the naked eye. Only by measuring both characteristics will you know if the plates are causing your problem. It's rare to have both slippage and draggage occur at the same time, but the conditions I described might be your answer. Hope this helps.
Your Suzuki service manuals will give you the tolerances for the measurements.

 

[mudpack]

You might also want to make sure that all pivot points and the clutch cable itself are clean, properly lubricated, and work freely!

I hope that all helps.

 

[ssaulnier]

Thanks for the reminders. Yes I have the manuals and yes I forgot to measure the friction disks and put the metal plates on a piece of glass to check for warpage.

You caught me. Yes it will help.

 

[mudpack]

A granite surface plate will be flatter than most pieces of window glass.
I bought a small granite surface plate from McMaster-Carr several years ago just to check flatness of small parts. It was under $200, IIRC, and it has paid for itself several times over.
It weighs a TON, but it is so cool.

 

[sr5bidder]

ssaulneir

yes you can try the ford type f tranny fluid it did wonders for my little dt100 (could never get it in neutral while running) and now its getting better every time we ride it.I have also put it in my kdx to see ... My steel plates do need to be replaced though

I'd just live with the rest untill it did not work well anymore and effected your riding then get a whole clutch kit plates discs and all for about 90 bucks. and stil be 110 dollars ahead and won't take the chance of a heavy piece of stone injuring you or your kids

you may find some who will say the manual calls for this, or the manual calls for that,
bottom line is if evryone always followed the manual their would be no such thing as Nascar or dragsters any how don't go on my word alone there are many who have used tranny fluid for years with no problem goto thumpertalk two stoke discussion

 

[IndyMX]

If my clutch was sticking or slipping, I don't think I'd just learn to live with it. Or not pay any attention to the manual, regardless of the success of Nascab & Drag racing.

The penalty for not fixing it properly could be a full body cast. or traction or maybe a wheelchair for the rest of your life.

The question is, what happens when the clutch fails on the face of a big double, since you ignored the manual, and just learned to live with it?

ssaulnier, don't pay attention to this guy ^^^.. Unless you don't really care for your kids much.

 

[julien_d]

Sticking is somewhat normal, as the fingers from the basket get grooved, the prevent the plates from separating completely. Many KDX's have the same problem, and it's something you can learn to live with.

As for slipping, you definitely want to figure that one out. Probably worn friction plates.


J

 

[sr5bidder]

indy, Dude said it was slipping with his 200 plus pounds on it I dont think it would be slipping with his light wieght kids. ANd as far as sticking he said it was only enough to make finding nuetral hard I believe it it would not stop rolling he would be replacing everything instead of asking.
Anyhow minor problems you have more a chance of some cocky dude on a full blown mx landing on you because "your on "his" track" and he only can take one line and your in it.
Too clutches just don't all of a sudden fail unless its a snaped cable.

And I was speaking in terms of fluid and the manual not specs and proceedures many have found a smoother transmission with atf.

 

[ssaulnier]

Thanks for all of your suggestions. I appreciate your time and effort. Last night my 12 year old son and I dissassembled our old family pc because the power supply died. First I took him shopping at the local Altex Electronics store where we got to discuss computer building with one of the staff. We ended up buying the same case and power supply that the staff guy used when he built his last PC. Then we went home and swappped all the cards and drives from the old case to the new one. We got done just around bed time and it fired up first kick! Mike was pretty stoked. :cool:

Now his 16 year old brother will learn how to dissasemble his RM125 clutch, measure the plates and install new clutch springs. We will also try the F type auto tranny fluid.

I can't wait to go riding this Saturday.

Thanks guys.