scored clutch?

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schrader7032
Posts: 7313
Joined: Fri Oct 27, 2006 3:00 am

scored clutch?

Post by schrader7032 »

Duane Ausherman has a discussion of various clutch assemblies on his website:

http://www.w6rec.com/duane/bmw/clutch/index.htm

I suspect you have the earliest version which may have some tendency to capture the dust although there's supposed to be a gap to allow the dust to escape. On my late model R69S, the pressure plate had the six donut spacers to give plenty of room for the dust to escape. I'm wondering if excess dust build up was part of your problem.

If you had to remove too much material to get the score marks off, you might weaken the plate and then it would flex too much and make the clutch operate ineffectively. Maybe some light sanding to make the surface smooth so it didn't cut into the disk. If you had to do more than that, I'd look for a replacement...

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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pierce7221
Posts: 38
Joined: Thu Dec 14, 2006 7:33 pm

scored clutch?

Post by pierce7221 »

great site, lots of good info, thanks. it even explains an unrelated problem i was having with my transmission :)

just to be clear here -- because i was confused when i saw the clutch, given that there were no weird noises or vibrations coming from the clutch when in use, and also that the clutch is above the minimum listed thickness -- the shiny metal parts are flush with the lining, and are scored in the same pattern as the lining. this is bad, right?

Image

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schrader7032
Posts: 7313
Joined: Fri Oct 27, 2006 3:00 am

scored clutch?

Post by schrader7032 »

Now that I see what you're talking about, the backside of every other rivet has done the scoring. You first indicated that the clutch thickness was 6.6mm, above the 4.5mm mininum thickness. Did you compress the fiber disk when making that measurement? I believe there are some small spring plates sandwiched between the two fiber surfaces. Since one set of the rivets has now become flush with the fiber disk...that would seem to indicate maybe some uneven wear? Plus the circumferential grooves don't look good either.

If it were me, I'd expect that the metal pressure plate is not usable and would replace the complete clutch package. It may be that the spring mechanism is not provided the uniform pressure when squeezing the fiber disk. I suppose you could reuse some pieces but my guess is you'll be back inside this clutch sooner rather than later.

I'd sure like to understand what's going on. You might try sending an email to Duane on the website I mentioned. Or you could also go to Boxerworks.com and register there (it's free) and pose your questions. Duane hangs out on that site as well. Of course there are other guys on this forum who might have more insight on this. Maybe they're out riding right now!!

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Allan.Atherton
Posts: 503
Joined: Fri Oct 27, 2006 3:00 am

scored clutch?

Post by Allan.Atherton »

... the shiny metal parts are flush with the lining, and are scored in the same pattern as the lining... this is bad, right?
The shiny things are rivet heads flush with the friction surface. The rivets are installed alternating from one side to the other of the clutch. The photo shows that the lining has worn down to where the rivet heads are flush with the wearing surface.
Here's a few shots of my spare clutch:
http://www.flickr.com/photos/roundel/sets/678305/

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pierce7221
Posts: 38
Joined: Thu Dec 14, 2006 7:33 pm

scored clutch?

Post by pierce7221 »

Did you compress the fiber disk when making that measurement?
i did not...


The shiny things are rivet heads flush with the friction surface.
and that's pretty bad, i assume.


Here's a few shots of my spare clutch:
http://www.flickr.com/photos/roundel/sets/678305/
you've got lots of great pictures there, i'll be bookmarking that for future reference. thanks.

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VBMWMO
Posts: 1322
Joined: Sun Aug 23, 2009 7:49 pm

scored clutch?

Post by VBMWMO »

the clutch plate and housing (and everything that the clutch is supposed to rub on) on my '55 R50 appear rather scored and ugly. not smooth. lot of dirt-looking crud rattling around inside the housing, too. but i checked the plate thickness, and it's above the minimum listed in my book (4.5mm -- mine is at 6.6). so i would have assumed the plate doesn't need replacing, except for the scoring. clutch made no odd noises and felt ok when riding. so, should i be worried about the scoring? does that mean i need to replace the plate/housing or have it turned on a lathe or something?
Dedicated to the Preservation of Classic and Antique BMW Motorcycles.

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