1979 R65 Rear Wheel Issue

[Mike V]

Agave,

With the rear wheel off the ground (motor not running) and the clutch dis-engaged (lever pulled in) can you rotate the rear wheel with your hand in any gear?

-Mike V.

[Rick]

Bob, there is no free play at all when neutral indicator is lit.  
Mike V  I can't rotate at all in any gear with the lever pulled in.

[Rick]

Just pulled the rear wheel with no issues.  It isn't the brakes hanging up the wheel.
The wheel will still turn if bike is running and in gear with wheel off the ground, but still frozen any other time.  Fearing a clutch/transmission problem that I didn't originally anticipate with this bike.  

[Mike V]

Agave,

I'm confused ... everything was fine, no issues until after you adjusted the valves?

Are you getting any rear wheel free-wheeling in any condition?

I'm wondering if your clutch splines / input shaft need service or your clutch plate is hung up.

-Mike V.  (puzzled)

[Barry]

I think we are all puzzled.  I thought Bobs question about slack in the various transmission components was a good one and would nail it down a bit.

So to recap - there is no rotation possible at all even with the wheel off. You would expect at least a little free play from clearance in the meshing of the  final drive gears. If that is totally non existent I really am puzzled as it would imply something seized in the final drive/rear wheel bearings.

If you can feel some free play then that moves the suspicion forward to the gearbox.

[Rick]

Mike V & Barry,, I know, I figured people were getting confused.
Recap:
Had rear wheel off ground while adjusting valves.  (Don't think the valve adjust has anything to do with this issue.)
After valves adjusted, started bike and ran it through the gears while rear wheel still off ground and shut engine off. Wheel turned OK.
When rear wheel was back on ground noticed that rear wheel was locked up.
No movement in wheel at all, no movement or freeplay whether engine is running and in neutral,  or running in gear with clutch, or not running in neutral.  Can't move it at all in either direction.
If running and put in gear with wheel off ground it does rotate, but didn't want to run it very much like that.  Still stuck after running like that.
Pulled rear wheel to verify brakes not stuck.  
Thats where I left it until I can dig into it starting at final drive and moving forward.

[Bob_Roller]

This may not help at all, but drain the final drive, shaft / swingarm, transmission oil and see if you may get a clue there, by the condition of the oil, metal contamination .

May be able to identify the faulty component, without any extra work .

[Mike V]

Stuck Clutch Plate?

Agave, try this: Carefully!

With the bike securely on the centerstand and the rear wheel off the ground hold the front brake.  Start the engine in first gear.  Do not disengage the clutch. Run the engine up to a medium rpm and aggressively apply the rear brake with heavy foot pressure.  If your clutch plate is stuck this may release it.

Try this a couple of times first then we can try the road method.

Has the bike been sitting for a while? Your valve adjustment had nothing to do with this.

[nhmaf]

Even a stuck clutch I'd still expect to see a little backlash/play in the rear wheel rotation in one direction or the other.   But maybe there isn't, or it is small enough that the owner cannot tell the difference.

Try pulling the plugs out of the cylinders, so you effectively have no engine compression to work against.   Push the bike off the centerstand and just try to roll it back and forth in your garage.   If you hear the wooshing of air out the spark plug holes when you push the bike then the gear box is in gear and is driving the engine.   Turn the key just far enough to light up your dash lights to see if the neutral indicator is on.   If it is - it is lying to you and the gearbox is really in gear.   Then try pulling the clutch lever in and pushing the bike forward and back - you should have room to do this 8-10 feet in either direction ideally.    If the pistons do not move while doing it this time, then your clutch is not stuck and is working OK.

You need to do some diagnostics to identify whether the problem is in the clutch, the gearbox, or further back, and this may help rule out some things.


I am wondering if this might be one of the infamous shift cam/pawl spring problems, where in it leaves the gearbox stuck in whatever gear it was in and one cannot shift out of it, regardless of the neutral switch indicator.   The only way to get the gearbox out of gear again is to turn it upside down - which is usually done with taking the gearbox out of the bike, rather than flipping the whole bike upside down.   Requires gearbox teardown to fix - I hope this isn't the case for the owner as it will likely  run $500 to repair, but if one is unlucky enough to have it happen, you really have no choice in the matter.

[Mike V]

I am wondering if this might be one of the infamous shift cam/pawl spring problems, where in it leaves the gearbox stuck in whatever gear it was in and one cannot shift out of it, regardless of the neutral switch indicator. The only way to get the gearbox out of gear again is to turn it upside down - which is usually done with taking the gearbox out of the bike, rather than flipping the whole bike upside down. Requires gearbox teardown to fix - I hope this isn't the case for the owner as it will likelyrun $500 to repair, but if one is unlucky enough to have it happen, you really have no choice in the matter.

I'm thinking the same thing or maybe another internal transmission / spline problem. But want to see if we can figure this out before wrenches get involved.

maf - doesn't the broken pawl spring reflect in a loose shift lever and inability to change gears?  I think Agave mentioned he could shift through the gears.  I'm eagerly awaiting the resolution to this one.

[nhmaf]

Mike-
Usually the pawl spring problem does result in a loose, but ineffective shift lever.  But, maybe something else has failed instead, or it really isn't shifting through the gears and just appears that way to the owner.   I am hoping for an inexpensive solution for the owner, and hoping the 'push tests with sparkplugs out' can help point us in a direction, or reduce the possibilities..

[Rick]

I didn't think a pawl spring problem due to the fact it was not stuck in one gear and I have been able to shift into gears.  
Couldn't do a push test with plugs removed because the wheel wouldn't roll, but that is a great suggestion to file away for future use.
I decided to remove the final drive unit.  Once removed, the drive shaft can be turned easily by hand but final drive unit couldn't be turned.  
I may have found the problem.  The nut was very loose that holds the drive shaft spline coupling hub.  I started tightening the nut down and as I did the final drive unit started to free up and turn.  The more it was tightened, the more free it got.  I assume this nut being loose allowed the bevel gear inside the final drive to move causing binding???  just my best guess.  Now to figure out how and how much to tighten that nut and make sure everything is OK. Hopefully nothing was damaged by running briefly like this with the wheel off the ground while trying to figure out the problem.
Kind of concerned as to how and why that nut got loose and how tightening it down can affect the bevel gear mesh/backlash though.  

[montmil]

Check shop manual for torque requirements. Additional info can be found on Snowbum's site within the final drive sections.

Very strange issue. You might consider yourself lucky that you found the problem in your garage rather than at 70mph.

[Bob_Roller]

Here's what the tool that is used to tighten the loose nut that you have .

http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_54&products_id=325&zenid=60da9e1041ab08ca00831d29b23095fd

[Barry]

Bob asked the smartest question many posts back. If there was no perceptible backlash at all when turning the rear wheel and it wasn't the brake then it had to be something to do with the final drive.  

Torque setting from the BMW repair manual is is 111 lb/ft  
That's a high torque figure and with the requirement for dry threads and loctite it's probable some PO didn't follow the correct method.