clutch graunch

[Chuey]

Timo and Chasbmw have said what led me to what is now a partial solution.

I took out the plastic throw out bearing without removing the transmission. Everything looked perfect. There was no dirt in there. The T/O bearing moves fine when it's cold but I clamped it into my vice (with blocks that protected it from any distortion) and used some sandpaper to slightly reduce the size of it. I have a roll of sandpaper that I found on a bicycle ride. I used it in a shoe shine type motion and from a few different positions in order to not make the part out of round. Then I installed it with a coating of grease. Also, I checked and the cable was 201mm at the specified place, so no problem there.

For the first twenty minutes of the ride, I was beaming with success. I started feeling what I didn't want to feel. Slowly, the graunch came back. It's not nearly as bad as it was but it did come back. I think I'll try sanding the part a little more.

Also, I bought a new T/O bearing part when I was at the BMW dealer. If you run your fingers around the circumference, you can feel that it is far from round. It does not feel as if it has designed in ridges or the like, but instead, it feels like sloppy manufacturing.

I am hoping I'm on the right track. I'll report back here. I would welcome any constructive ideas.

Chuey

[Deleted User 72]

I don't remember the details from my last foray in there. But, if you can mount the plastic sleeve from the T/O bearing in a drill and spin it against your s/p the job may go a little smoother (and rounder.)

[Chuey]

The clutch graunch is gone. It is fixed. No Problemo. HooWee!

While at the BMW dealer, I picked up a replacement clutch release bearing...throw out bearing. I figured I'd try another new one. Important point: the one that had caused the problems was new as well. I pulled out the old one and measured both of the plastic housings for diameter. The new one is two tenths of a millimeter smaller! That is after I had sanded the outside of the original one. It turns out that I hadn't removed much material from the original as you could still see spots where the original, shinier finish hadn't been abraded by the sand paper.

On the shake down ride with the new part, the clutch worked better than any airhead clutch I've ever used. Man, it is crisp and the release is perfect! I realize, now, that the clutch had been balky all along. I had thought the splines may have been damaged but Duane had said that the splines don't affect clutch release and I can see why, as they simply allow the disc to float, or not. Anyway, I'm stoked. The bike runs very strong.

Chuey

[Steve in Golden]

Cool, glad you figured it out.

Could the original bearing have been the wrong one somehow? Should be the exact same size.

[Duane Ausherman]

Glad that you found the fix. Did you get the "bad" one from an authorized dealer? Even a dealer could be buying parts from another source.

Long before I was an official dealer, I ran a very successful pirate shop for BMW. Parts were always a problem and I found that many could be purchased from the original manufacturer. The trick was finding out who made what.

A few times I found that some aftermarket source had parts that "looked" OK, but in fact were not the same. A couple even worked better than the originals. Some were defective right from the start. You may have one of those.

That is how I found Nural and was able to buy pistons for $5 and from Butler and Smith they were $29 and retailed for $50. Didn't use enough pistons to have it be a major profit center, but it helped out a bit. I got clutch plates for $.75 and the retail was $16 then. That too wasn't high volume, but helped out.

B&S only had a gross profit of 40% and all other brands was 50%, or double the wholesale price. Most BMW dealers didn't allow the parts book to sit out on the counter, or customers would discover that they were paying too much. We only sold for exact retail and the parts book with prices was on the counter.

The fact that we stocked just about everything gave us a huge advantage, as riders slowly learned that they had to go to BMw of Marin to finish off any list. So, they would save time and trouble and come to us first. That gave us slightly higher volume.

The shop had 4 full time year around mechanics working only on BMW motorcycles, so we did more repair work than all of the 6 shops in our area combined. That helped too.

I sold parts by mail too and that helped a bit. We fixed up a lot of wrecks and that helped. Getting a few parts for almost nothing helped too.

Oh, I went off topic again, sorry.

[Chuey]

Both parts were new BMW parts bought over the counter for cash at BMW dealers. I recall the first one costing around forty or forty five dollars and last week I bought the new one for sixty five.

It is a lot more gratifying to pay sixty five for a part that works than any dumb deal I could have gotten. It took a lot of joy out of riding the bike to have the clutch work wrongly. Also, it was dangerous at one point when the clutch couldn't be smoothly engaged and it had the same effect on the drivetrain as would a terribly inept user.

It is my hope that by posting my experience here, someone may benefit from it. I'm pretty sure at this point, that if I'd taken a little off of the outside diameter of the first part, it would have fixed the problem. Duane, this is the new part that BMW dealers will have, going forward. It would seem to me to be a real benefit for you to include in your website, a tidbit about the possibility of these being oversize and that being the cause of uneven clutch release when the machine is hot. If you wish to include it, and need part numbers and/or measurements or photos, I'll do my part.

I've mentioned here before how my feelings of self worth are loosely tied to feelings of accomplishment tied to fixing things. Today, the good feelings stayed with me through the day. Being overly simple has its advantages.

Chuey

[Airbear]

Happy news Chuey, apart from the $65 slug. It's good to get your graunches under control, and the time spent will be added to your life because you solved the problem and shared your experience here.

And Duane, thanks for that 'trip down memory lane'. 75c clutch plates? $5 pistons? Crikey!
This old fool is peering short-sightedly into the far distance, trying to remember what the seventies were all about.
It's all a bit blurry I'm afraid, but I seem to recall some fun parts.

[Chuey]

Pulling the clutch lever is unrelated to the splines. You are grabbing at straws on this one. Did you check the input shaft end play before installing the box?

Always do that, as it is easy and may save a swap later on.

Duane, have you read what I wrote?

Chuey

[Duane Ausherman]

Chuey, are you talking about this part?

I am starting to wonder if it is the splines. I did use some grease on them and it has very few miles on it since then. However, when I got the transmission, there was light rust on the splines. I cleaned the rust off and greased them. The disc seemed to slide smoothly on the splines. I've got a pretty good parts stash. I maybe should see if there's a spare late transmission in there.

Chuey
Chuey Posts: 3946Joined: Mon Aug 02, 2010 8:56 pm


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Re: clutch graunch

by Duane Ausherman » Tue May 29, 2012 3:52 pm

Pulling the clutch lever is unrelated to the splines. You are grabbing at straws on this one. Did you check the input shaft end play before installing the box?

Always do that, as it is easy and may save a swap later on.

I was just asking about the input shaft end play. If it is excessive, then you will get the grabby feeling. Or am I still missing something?

[Chuey]

Chuey, are you talking about this part?

I am starting to wonder if it is the splines. I did use some grease on them and it has very few miles on it since then. However, when I got the transmission, there was light rust on the splines. I cleaned the rust off and greased them. The disc seemed to slide smoothly on the splines. I've got a pretty good parts stash. I maybe should see if there's a spare late transmission in there.

No. I was talking about this part:

I had thought the splines may have been damaged but Duane had said that the splines don't affect clutch release and I can see why, as they simply allow the disc to float, or not.

It is in a later post. I think it's the one before the one where you asked if it was "this part".

Chuey

Edit: It is in the last paragraph of the third post of mine prior to this one.