Bugger. Me clutch's gone? Or maybe not?

**Ixion** · 1st February 2006, 18:45

Odd. Took the BMW to have a new tyre fitted this arvo. All fine over to the Shore and back to Wiri. Come time to go home, jump on , start up, onto the road - WTF? Clutch is sllipping like mad. Stop, check cable adjustment, look for anything obvious, nothing. Off again, still slipping. No noises, no judders or jerks, just slips at anything over about 2500 rpm. Seems Ok up to that point. Limp slowly home - not too bad, cos I can still take off from a standstill OK, and 2500 RPM is about 70kph in top.

Get home, wozza matter wiv the bastidge? Clutch plate gone? Not the usual symptoms, and no warning at all . Splines rooted temselves? No noises or jerks, seems too smooth. Pull the rear wheel off and slip the cable off, and slacken off and readjust the pushrod adjustment (Yes, you do have to take the wheel off, it's a BMW don't expect anything normal). Hmm, everything looks OK. Unfortunately, a clutch on a BMW is a BIG job - not like a normal bike. Well, ever the idiot optimist, I'll just try resetting the pushrod, and reassemble. On the thousand to one chance. And bugger me, do so, onto the road, and it seems fine. Pulls away from 1500rpm in top with no slip, runs up to peak revs, no sign of slip.
Very odd. Very odd indeed. Problem is, now I don't trust it. Anyone ever encountered such a happening?

**HDTboy** · 1st February 2006, 18:56

Is it a dry clutch? If so is there oil on the plate or leaking out of the bellhousing?
If you dump the clutch in dop gear (as hard as it sounds) you'll soon know if it's going to slip or do wheelstands

**Ixion** · 1st February 2006, 20:13

Yeah, I thought of a seal blowing and soaking it in oil (it is a dry clutch). But no oil leaks, and an oil soaked clutch won't right itself. It doesn't slip under hard take off - (don't fancy slipping sideways off the clutch lever on a shaft drive, theres nothing to coushion the blow, you can break a tooth off the pinion that way).

**HDTboy** · 1st February 2006, 20:39

How many times have you done it in a car without worrying about the crownwheel, I could give experience a call tomorrow if you like

**Ixion** · 1st February 2006, 20:47

I'll just wait and see - it's not slipping now. I have seen something like this once in a car where a bit of lining broke away and got bent back and caught between the (unbroken away) friction surface and the pressure plate - so there was only a very small area taking the load. When the broken bit broke away completely it "fixed" itself. I think I better think about scheduling a pull down sometime soon, probably a good idea to lubes the splines if nothjing else. Least I may be able to do it at my convenience, anyway

Thanks anyway.

(Uh, never in a car - I don't like abusing machinery if I don't have to. I've seen a good many pinions and crownwheels with broken teeth though)

**N4CR** · 1st February 2006, 21:40

Well after you have gone past me now twice sitting on the tank on one wheel - I'm not suprised.

I have no idea how these things work but mabey a minor oil blockage and it got dry or something!?

**Mooch** · 1st February 2006, 22:07

Was the rear tyre getting replaced by any chance ? .... Have you checked the rear gaurd for small chunks of rubber ?. If you find small bits someone may have finished off the rear trye and your clutch at the same time.

**Ixion** · 1st February 2006, 22:46

No, it was the front. And I watched them do it.

**Ixion** · 2nd February 2006, 17:17

UPDATE: Rode it to werk today, then into the city and back. No problems at all, no slipping. So buggered if I know what that was about , but at least it hasn't cost me any money . Yet. OK now, so that rules out most common clutch deamons. Could still be the lining shredding off - in which case I'll know soon enough I guess.

Literature search turned up one other possibility - the pushrod actuating arm pivots on a shaft which in turn is supported in two needle roller bearings. Which have a (mild) reputation for crapping out. On account of no-one made any provision to lubricate them. Thought the Herrenvolk were supposed to be through. I have known crapped out needle rollers to partially seize as broken rollers jam up, thus maybe preventing the arm returning fully. And my resetting adjustments freed things up. Maybe . Perhaps. I'll put pulling the bearings out and checking them on my list of "Stuff to get round to when I have some spare time". 'Tis a long list, that, but.

Anyway, it's all good for the moment.

**Motu** · 2nd February 2006, 17:29

I've been thinking about this all day,a tricky one alright...but think I've got it sorted.My diagnosis? - Senior Moment.....

**Ixion** · 15th February 2006, 20:30

Took him for a WoF today, then on to werk, all good. Stop at the servo on the way home for petrol, set out again, and it's all revs and no action!

But this time I stopped and investigated.

Peering suspiciously and critically at the pushrod actuating mechanism. Looks ok, and a tentative prod with a finger (access is limited) seems like it is fully back . And pulling the lever in and out, and such like makes no difference.

But. But. When I deployed BMW special tool IX-001-A (aka, my umbrella) in a retrograde axial aspect, in conjunction with BMW special tool IX-002-B (aka a BLOODY BIG ROCK that came conveniently to hand from a nearby garden feature, very obliging of BMW to provide convenient roadside repositories of special tools) a further 3/8" or so of movement resulted (in technical terms, I stuck my brolly through the swing arm to prod the clutch actuating arm, and gave it a blurdy good whack wiv de rock ) .

And then the clutch clutched like a clutch did orta clutch.

So I think I must move investigation of those needle rollers higher up the list.

(BTW, I am always surprised at how few motorcyclists carry an umbrella. The folding variety are small enough easily to be accommodated - bungy them to a convenient frame member. And I have many times found the brolly to be useful - as well as it being very handy for keeping dry in the rain, of course.Word to the wise)

**raster** · 15th February 2006, 20:49

Hope you get The White Wale sorted, I'm sorry I haven't got any bright ideas for you, I ended up breaking my clutch

**Motu** · 15th February 2006, 21:17

So do you reckon a trampoline spring hooked onto the lever and back to a hole you can drill in the swing arm will fix it?....

I'm sleeping on my tramp tonight....just incase you get ideas...

**Ixion** · 15th February 2006, 21:23

That's OK - I just need the springs. Suggest you put something soft under the tramp.

**Milky** · 15th February 2006, 22:12

I believe that the later clutch actuation systems are much improved on the earlier ones. They went from thrust ball bearings to radial needle roller to radial needle roller + integral hingey thingy AFAIK. It is not an unheard of problem for these bearings to fail.

As an aside, do you have the requisite grease for the clutch splines?