Clutch or gearbox?

[arvo92]

The problem started with my last ride. I pushed in the clutch at the handlebar and suddenly the pressure at the handlebar was gone and the lever was totally loose, almost hanging. I could feel some weird snap at the handlebar when this happened. I finished the ride without using the clutch and got back home.

2 days later I adjusted the clutch at the handlebar. It sort of worked, so I could feel the clutch actuation is there. But another snap was feltable. I started the bike and engine runs as normal. But the bike would not move. I could feel the gears moving up and down but still no movement. Like the clutch is constantly on.

I have thought about it and it feels like a clutch issue to me. The rear main seal has been leaking previously, I myself have not noticed any oil flow.
I do have changed the clutch actuation before. it was obliterated by previous owner. I have never taken the clutch apart but I do not believe in it too much as I saw the condition of clutch actuation.

If gearbox was a goner, I could hear some rattle there, right?

[Matt Chapter]

Your clutch cable is broken, I would think.   The feeling at the bar is unmistakable, in my experience. Mine tended to break just behind the round widget on the end, at the handlebar...  You could also have a kink or something in the cable holding the clutch open.

[Bob_Roller]

I would check the cable to make sure there is not a problem with it, as Matt has said .

If you don't find anything there, I would check the adjustment bolt on the clutch arm at the back of the transmission .

When I replaced the clutch on my '81 R65 about 7 years ago, after I adjusted the bolt, I neglected to tighten up the jamnut on the bolt and the bolt came out about 10 miles from home on the first test ride .

I was lucky, ACE hardware stores carry metric hardware stopped at one, before I really needed the clutch .

[arvo92]

Hmm. Clutch cable is actually on the brink of collapse. Exactly as Matt described - behind the round widget. The cable is not totally broken but several threads of steel wire are gone, around half of them.
I noticed it when the handlebar started to hang freely.

So it is not possible to jam into gear without using the clutch? I thought it was...

And - does anybody have the specs for the cable? It is impossible to get a new on in this country but there is a pretty neat tractor supply store here which has lots of good stuff for soviet motorcycles as well. They might have the same length cable.

[Tony Smith]

So it is not possible to jam into gear without using the clutch? I thought it was...

Of course it is. A few years back when I was a bit poor I rode the R100 for several weeks with a broken clutch cable. Start the bike in neutral and warm it until it will hold normal idle. Push off (it helps to have a little slope here, like a driveway gutter or the like), snick into gear and ride away. Nice slow deliberate gear changes carefully matching the revs will do no harm to your gearbox. If you need a standing start on level ground, select 1st gear and pull in the clutch lever (for the sole purpose of closing the lockout switch) and press the starter button, when the engine catches accelerate away briskly to minimize "snatch" in the gearbox.

And - does anybody have the specs for the cable? It is impossible to get a new on in this country but there is a pretty neat tractor supply store here which has lots of good stuff for soviet motorcycles as well. They might have the same length cable.

You don't need it. Bearing in mind that your partially broken clutch cable has stretched a few millimetres, buy a length of the correct diamter cable and the appropriate "ends". Solder the handlebar end on first and remove old cable and insert new cable into the existing outer (or cut a new outer to the same length as the old one) Set handle bar and gearbox cable tension adjusters to minimum and use this to guage the correct length of the new inner. Cut cable appropriately and then solder on the "end", refiit to bike and happy riding.
 
A quick note on cable cutting. If you do not have access to a proper cable cutter, use a small torch to heat the cable annd run a small amount of solder into the cable at the cut point, the cut the cable with a cold chisel.

[Luca]

You can change gears without the clutch, but downshifting is trickier than upshifting and starting from a stop is a whole different matter. You'd pretty much have to kill the engine at every stop and get it rolling in first gear with the starter motor.

None of this is good for any of the associated parts: shift forks, dogs, starter motor, ring gear.  Once you get the bike safely home I'd leave it there until you fix the problem.

If the clutch cable is fraying at the handlebar lever, you should make sure that the round widget can rotate freely.  When they don't, the clutch cable strands get fatigued, start to break, and soon after that the whole thing snaps.  A replacement cable will live a short life if that problem isn't fixed.

Since your cable is as good as dead, I'd just take it off the bike and bring that to your tractor supply place.



Unfortunately, though, I'd be looking at the clutch arm on the back of the transmission since your cable isn't totally broken and the clutch isn't working.
-I'd check the lower adjustment bolt and make sure the clutch arm still has good threads for it to screw into.
-Make sure the clutch arm pivot is still mounted through the clutch arm and the two ears on the back of the transmission.
-Make sure both of those ears are still there.
-after that, start taking the throwout parts out of the back of the transmission and look for anything obviously wrong.

[arvo92]

A quick note on cable cutting. If you do not have access to a proper cable cutter, use a small torch to heat the cable annd run a small amount of solder into the cable at the cut point, the cut the cable with a cold chisel.

Thanks for the tip. I will use this method. Back in the days I was 14 we would make the new cable end by using a bolt nut. Place the nut around the cable and slam it hard with a heavyweight hammer. Sort of works And my father told me recently that he in his youth used the same technique and it was commonly reccommended as new parts were impossible to get and if you wanted a new part, you had to make one yourself.

I actually tried to run together with the bike on neutral, engine running and then jumping on and slamming 2nd or 1st gear. Did not do the trick. That is why I thought it is the gearbox. But now I am more sure I just did not get the gears engaged.

Unfortunately, though, I'd be looking at the clutch arm on the back of the transmission since your cable isn't totally broken and the clutch isn't working.

I have changed the whole clutch actuation assembly together with the arm very recently. I doubt the problem is there. I checked visually back there and everything is where it should.

The round widget totally  moves as it should. The previous owner had neglected the clutch actuation and when the springs and bearings broke, he had adjusted the round widget to its maximum so clutch could engage. That is why I think the cable is fraying from there.

[Matt Chapter]

Here's a tip that came back to bite me eventually... The round end of the cable sits inside a cylinder that fits into the lever.  If you don't have that cylinder, the cable will snap again, sooner rather than later, because it will wear the inside of the lever into a sharp point.  Then you need a new lever and cylinder and cable.

I tried to find it on max bmw's fiche, but it doesn't seems to be listed.

Also note that as soon as the cable fully breaks, that cylinder will drop out of the lever, so if you're riding, it's as good as gone.

[arvo92]

Also note that as soon as the cable fully breaks, that cylinder will drop out of the lever, so if you're riding, it's as good as gone.

Thanks, Matt, i will take it into account. Luckily the cable still hangs on, barely. I did know there is a cylinder there but I did not know that it might just pop out like that.

[arvo92]

Clutch or gearbox? Neither.

Today I finally got to the bike and as I dismantled the clutch cable, it fell into half. Exactly where the round widget meets the wire.

What I noticed was that even when the cable was in half, the clutch arm was still in engaged position. The cable strips had blocked inside the outer coating. Instead of being parallel with the back of the gearbox, the clutch arm was under steep angle towards being pulled in. So that explains why I could change into any gear I wanted and the revvs went sky high instead pulling the bike.

So now I have the cable out and ends with me, I will try to see if I can make myself a spare part or not. Soldering the ends is probably a bit trickier than using solder for electronics (I have no idea yet!)

[Barry]

Having done it many times in my youth it is possible to solder a cable nipple but it is much harder than electronic soldering mainly because of the difficulty in getting the cable truly clean and also because the metals involved are just harder to 'wet' with solder than copper or tinned copper. You really want high strength solder and active flux to stand any chance of success.