ADVrider (
-   Crazy-Awesome almost Dakar racers (950/990cc) (
-   -   Clutch troubles (

Unruled 04-08-2013 01:48 PM

Clutch troubles
Hi guys,

I've had a 950S for a while now (2003, first European year) and am quite content indeed. It does have one small issue though, being the clutch. I know that KTM threw a wobbly when they designed the thing, and it's a weak spot. But I can't seem to find exactly where the problem is located and what's needed to fix it. I need the bike every day and can't (time-wise) afford to take it apart, assess damage, put back together and fix some other time.

Symptoms are limited to a very snappy clutch when the engine is cold. There is no vague feel (slave has already been replaced... by new original unit, but functions fine) and it completely disengages, doesn't slip when engaged.

However, when riding away with a cold engine I have to feather the throttle and ease the clutch out carefully, otherwise it lashes back, whips the chain rather uncomfortably (chain tension is set correctly) and I'll be lucky if the engine doesn't stall in the process (northern Europe, it's around freezing point here in the mornings, so cold means cold). Problem seems to be getting worse the past 2,000km (1,200mls).

Is the unit completely shot or is it a simple fix? Haven't checked the oil jet yet, but surely it can't be just that...

gefr 04-08-2013 02:31 PM

It could be oil reduction jet.
Also the central nut being loose and/ot the deeper steel disc having a groove developed from friction to the belevil spring. I suggest you check all these. Not too much time needed. 1/2 an hour if you do not get you hands dirty(using gloves) or another 10' for washing hands. Cheers.

dogsslober 04-08-2013 04:29 PM

Check the the booster to

keener 04-08-2013 09:12 PM


Originally Posted by gefr (Post 21138588)
Also the central nut being loose and/ot the deeper steel disc having a groove developed from friction to the belevil spring. I suggest you check all these. Not too much time needed. 1/2 an hour if you do not get you hands dirty(using gloves) or another 10' for washing hands. Cheers.

Not hi jacking the thread, this will help the OP too:

I have exact problem as the OP but it does not happen on every cold morning. Its sporadic.

The other day, I took the clutch cover off, took all the plates off and measures the pack. It was within spec as 50.50mm so as all the disks and plates. Springs were just above the spec at 29.45mm. BUT the last disk had the groove you are talking about. I can't see how the groove can't happen! That disk is right against the spring washer.

How does this groove can cause snappy clutch with cold oil?! I'm puzzled and very curious.

ATT OP: This was a 30 min job. No oil lose with bike on side stand. I put couple pieces of plywood under the rear tire just in case. Keep in mind you have to torque 6 bolts holding the springs to 10nm which is critical as far as I know.

Unruled 04-08-2013 10:55 PM

Thanks guys, going to look into that. Is the clutch seal going to fail or can it be reused? Still have to figure out where to easily order that stuff over here...

I can understand why that groove might be a problem, but also not quite sure why the problems would fade when hot? I'll also have to figure out how the booster works, previous bike didn't have one :P

gefr 04-08-2013 11:08 PM

The booster has these ramps that push to each other as the clutch tries to slip
The one part climbs on the other and they lock causing higher pressure to the clutch discs against the pressure plate.
The grove reduces the force from the belevil spring, because it loses some tenths of a mm, as it rests in the groove. So its function unsticking the clutch discs is compromised. The grooved disc needs to be replaced with another one.

jfh 04-09-2013 01:07 AM

Hello Unruled,
you describe the symptoms well in your post. I've had similar for some 4000 miles. When I clean the clutch oil jet the symptoms disappear only to return gradually (or am I being more careful when warming up - as you say clutch works fine when hot).
How many miles has your bike done? Mines an 05 Adv on 30000+. Orig clutch.
Has anyone taken out the clutch booster and reprofiled the ramps with a file or grinder?

roookie1 04-09-2013 04:45 AM

Im guessing oil jet. Try and pump the lever 2-3 times just before takeoff..and when You get time for it, clean the jet. Doesnt take to much garagetime..

Marc Lenssen 04-09-2013 04:53 AM

Had the same on my 04, hell to get away in the morning...renewed the oiljet but that didn't solve the issue. In the end I just bought a young but used 990 clutch (complete thing) from *bay for about 130$ and exchanged the whole thing, smooth as silk now even when freezing outside...
My old booster had quite some play after 30K miles....


Kiwi Pete 04-09-2013 09:08 AM

Hey mate, it's already been said but just to repeat: it's the belevil ring cutting a groove into the inner steel clutch plate.

This started for me in Peru a few years ago - ever since then I've been swapping the inner ring for another one every 6-12 months depending on amount the bike's getting used. I'm about halfway through the pack!

Easy fix.

Unruled 04-09-2013 10:32 AM

Alright, guess it must be the inner ring if so many of you think so. Will also clean the oil jet while I'm at it (have time this weekend). Just to be sure (as I have the first year model...), which one should it be? So I can check it's been changed to the right one...

Marc Lenssen 04-09-2013 10:50 AM

First year 950 Adventure might actually still have no oil jet at all, just a plug that closes the hole. Just order a current yet, they are cheap and you know it is open then, They also changed the design of the jet somewhere later on, the hole is in a little mount so that it does not clog up so fast.


Unruled 04-11-2013 01:54 AM

Defenitely worth checking then...

Also noticed something funny this morning, I (for completely unrelated reasons) changed the idle from 1500 to 2000rpm, problem is a lot less now... weird.

Unruled 05-18-2013 12:48 PM

Fiiinally fixed it.
Took me long enough, but I finally got to fixing the problem. Had the extra disc lying around for a while but just didn't get round to fixing the problem. It's warmed up a bit around here and the problem was less obvious while my schedule was properly full. Problem got worse however (last week was HELL, stalled a number of times in the most inconvenient places), and I really couldn't postpone the operation any longer.

Had I known fixing it would take 10 minutes, I'd have done it earlier, obviously. The "it's the belleville spring" crowd was 100% correct. Seriously groovy stuff.

Took a testride and it's sweet as a nut again.

Thanks guys :)

Times are GMT -7.   It's 10:23 AM.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2015