newbie clutch Q:

[suecanada]

Rob and Biocruiser, I just want to say that I have found this thread MOST enlightening! Thank you very much! I'm going to print it out! Rob's description of "what is what"  needs to maybe go into our tech section here??!

[Biocruiser]

I've always been the type to figure things out backwards... generally I start with the most difficult repair and work my way back to the easiest. Must be a mental defect. In any case, here's the re-cap:

• was riding bike and lost the ability to disengage the clutch. I managed to limp home.
• Decided it must be the clutch friction plate. Ordered one online. Waited a week. It was the wrong one.
• With the help of all of you I determined the correct disc. Bought one at the local BMW dealer.
• Pulled the tranny and installed the new plate. Also drained the gear-box and replaced the oil (it was watery).
• Replaced the final drive oil.
• reassembled the bike, no love.
• Pulled the clutch throw-out piston and found a pile of junk (exploded bearing)
• replaced bearing, race, and rubber gaskets.
• adjusted clutch cable to max. tightness (shortest?)
• clutch now operable, but still slipping with hand lever held all the way in.
• pulled clutch control lever again and removed the adjustment bolt at the rear of the arm.
• found it was quite squished at the business end
• replaced... with a longer bolt of the same thread pattern (for testing, I'll get the correct one...)

No love. I think maybe the pushrod is bent or... otherwise non-functional. I was trying to avoid pulling the whole transmission, swing arm, etc., but it looks like I have to. %^$&

[Rob Valdez 79 R65]

The transmission comes out WAY EASIER the 2nd time.  You will be pleasantly surprised.

Have you installed a new neutral switch, yet?  This is the best time to do it!

It is possible that the push rod is bent, I suppose, but more likely the inner race is stuck to it, and the tunnel.  This job is not finished, and I don't want to criticize, but you need to do this right if you want a reliable and fun ride.

I had one of these bearings destruct on me back in the early eighties (on my R65).  I learned a lot, that day, and I have never had a second one go bad.

[Biocruiser]

The rod is definitely stuck in there. I pulled the tranny again and I can't seem to get the rod to come out of the case at all... from either  end. In fact the end that pushes on the pressure plate is kind of mashed up (I think it can be smoothed out with a file)... should I just grab the rod from the back of the gearbox and pull?

[Bob_Roller]

I would remove as much of the offending material that has moved from it's original shape, if you get the pushrod stuck in the transmission input shaft, it's about a $350 part, and a transmission teardown, probably would end up being an overhaul, in the $600 area.

[Rob Valdez 79 R65]

With that mess at the front end, I would do my best to drift it out from the rear.

You do not want to hammer too hard.  You can easily damage the bearings on the input shaft.  
I just learned this the other day, reading about transmission shimming:

http://www.boxerworks.com/phorum/read.php?f=1&i=218659&t=218580

[size=12]"As for tapping the shafts to seat the bearings after assembly, be careful that you don't damage the bearings in the process. Even a soft mallet has the potential to cause the balls to dent the track (or "race") if used indiscriminately and so shorten the life of the bearings. It's a common reason for premature bearing failure. If you feel the urge to use that mallet, at least try to do so with the shafts turning and the housing warmed up."[/size]



Unfortunately I am afraid I have to recommend replacing the push rod as well as the pressure plate, since that is what the push rod contacts.
I would not be surprised if you could pick up a used push rod for cheap.  As I have said before, if I were replacing any clutch (surface) parts (such as the pressure plate), I would go with new.

[Justin B.]

I don't think I've ever seen a pic of a rod messed up like that before.  But, I suppose if the throwout bearing was frozen then the rod would effectively "spin" against it's pressure point on the pressure plate and cause melting/deformation like this.  Nasty, for sure...  Seems I mentioned the throwout bearing being suspect back in post #15 ...

If you can't "tap" it out from the rear with a suitable punch then maybe you can push it forward a bit and grind the "mushroom" shape off the front of the rod and get it to tap out the other way?

[nhmaf]

I don't know much about the earlier clutch models, but if it were me and this were my lighter flywheel '82, I think that I'd grind/cut off that mangled
tip and draw it out the back.  I don't think that one can get the rod separated from the 'cup' at the other end easily without pulling it out the back first,
 leastwise on the 81 and later models.

Like my grandpa and my father kept telling me, if you're going to do a job, you may as well do it right !


Good luck - I am sure that when you are done with the thorough repair and inspection, this bike will run and ride great.  And just think of the wonderful
educational experience you're accumulating with motorcycle mechanicals  !
 

[Rob Valdez 79 R65]

This bike IS worth the trouble.

It is easy to imagine that this is what got the bike parked, by the previous owner, in the first place.


And yes, Justin, you did mention the throwout bearing early on in this thread.


nhmaf: I have never taken apart a later model throwout assembly, so I cannot comment on it.  Looking at the microfiche, it is obviously a different animal.
I do know that the older ones have these radial-roller bearings, while the newer ones used a cage of ball bearings.
The later is better, because with the roller bearings, the inside part of the bearing is trying to spin faster than the outside.

Clean and inspect annually, is my motto.

[donbmw]

You can remove the rod from both ends. With the damage you have I would pull it out from the spline end. The race the bear rides on will slip right off the rod.  There is a felt pad that goes on the shaft up close to the bearing end. Put some oil on the pad and place it on the rod and slide the rod back in from the input shaft spline end and squeze the pad while pushing the rod. My R90/6 had the bearing go bad and the rod was welded to the pressure plate. If you find that your clutch fells funny and you have to start adjusting the free play very often you will fine that your the bearing is bad or going. The rollers type will probley be the one to go bad more often than the ball type. I have over 80,000 on my 82 R65 and I am change the ball type  on this bike because there is a rust spot on the cage and marks on the race. The boot has a small fold after all these years that may have let some water in. I am also changing the boot at the transmission and for the speedo cable.

Don

[Biocruiser]

Still not able to get the rod to come out... either though pulling, "drifting," begging, cursing... maybe I need a bigger hammer.

[Rob Valdez 79 R65]

re: bigger hammer

I am pretty sure you are joking.  Just remember the warning about the bearings.

You may need some sort of rotary tool to grind down the offending "mushroom" on the tip of the pushrod.

[donbmw]

You do have the inner race out of the push rod hole Item #3. It could be stuck on the shaft. Also where the felt pad goes on the shaft  item #2 I could see alot of build up of  pieces from the bearing that went bad not letting the shaft move. The shaft well come up both ends when every thing is working normaly.

Don

[Biocruiser]

It came free... just needed to tap the bearing end a little harder. The bearing race had welded to the rod... with the bearing disintegrated it was causing the rod to try and bore through the pressure plate. Rod and felt to be replaced...

[Justin B.]

Yecch!  [smiley=puke2.gif]