Clutch Rattle

[Philip]

I have a 08 GS with 25000 KMs on it and it has recently developed a rattle/knock in the clutch. This is noticable at idle and can be quite loud, so much so that sitting at traffic lights you just have to hold the clutch lever in as when pressure is put on the clutch lever the noise goes.
The local dealer says it may be the gearbox not the clutch - anyone with any ideas ??

[Cactus Bob]

Sounds like a similar issue I have with my '04 GS. Obvious rattle in neutral with the clutch released. I've got 80K on my rig so just assume it's an aging clutch and it doesn't seem to get any worse or effect shifting. Don't really see how it could be a transmission problem ... I'd be interested to hear if you find out anything more.

[pdxrmccgs]

There has been quite a few hydraulic clutch assist bleeding issues
on the forums that you guys might want to check out to increase
your trouble shooting knowledge base. Caveat: the clutch assist
circuit uses mineral oil and not brake fluid.

Welcome to the forum.

[Cactus Bob]

Thanks for the welcome ...
did a bit of searching but didn't come up with much. Search skills might be weak though. Not sure how clutch bleeding would play a role, but maybe you could tag a relevant thread? Thanks for any input.

[pdxrmccgs]

Sorry my post was kind of cryptic. Guys start to have problems with
getting the clutch to engage or disengage which leads them to trouble
shoot the "hydraulic clutch" which is really a hydraulic clutch "assist"
system. The first step is to drain or bleed the system and then it
is easy to take off the clutch assist piston cover and inspect the
piston rod that actually does the pushing. Sometimes this shows
that some service is needed to get the "piston" working properly.

The system is really fairly simple and it seems that some knowledge
about it helps trouble shoot clutch issues. Or to put it another way
if you know or have a mental image of what happens when you pull
the clutch lever you have a better basis, if you hear or feel weird
stuff, to go to the worry beads or just smile and head down the road.

The site was just sold and they did an upgrade but looks like
the archives and old threads disappeared.

If you go to this forum "Home" and enter parts Fiche R1200GS 08-09 (K25)
and go to 21_0196 Clutch Control it shows

Part #8 Push Rod, spherical
Part #2 Output cylinder clutch

These are the parts that some guys find causing issues sometimes.

I tried to copy the parts diagram for you but no worky.

Apparently issues arise as no one changed the clutch fluid and
it got real dirty or someone used brake fluid instead of mineral oil.

If you grab a handful of clutch and nothing happens this seems to
be where the problems exist. If things are just squishy that is probably
air in the hydraulic line indicating air bubbles during refill.

Hope this helps.

[Cactus Bob]

Thanks for taking the time to expand on this. I went into the fiche and found the diagrams on clutch components - I appreciate the advice.
Clutch action is good ... no problem engaging/disengaging. Just that slapping sound in neutral. Makes me think of a clutch plate flopping on the spline or something.
Not sure if this is what Philip is talking about.

[pdxrmccgs]

Here is a good animation on the transmission.

http://www.gadgetjq.com/transmission.htm

[Philip]

Well quite a bit has happened since I first post. The rattle didn't get a lot noisier but I was experiencing vibration in the foot rests, particularly on the overrun. This was begining to indicate a rather expensive fix.
On dismantling the clutch and gearbox the BMW agent has found that the vibration damper on the input shaft has cracked around the mounting, this is obviously a manufacturing fault and the first that they have heard of and because of this BMW are picking up the tab for the repair. In New Zealand there is only a 2 year warranty period, don't know why, when most of you you I think have a 3 year warranty.
I won't have the bike back for a couple of weeks as the parts have to come from Germany.

[pdxrmccgs]

Folks have different names for clutch parts. What are they referring to
as a "vibration damper"?

[marc]

This is a picture of an airhead input shaft from Anton Largiader's site. I believe the current transmission is not much different.



The broken part on the shaft on the right is part of the input torsional damper. Oh, here's a R1200GS tranny picture with a better explanation from advrider.