&#%@+ 250SL!

[Darrell]

Bah, I've just installed my third countershaft in a 250SL -- the splines have been shearing on the sprocket. The problem appears to be unique to me and my 250, but that's a digression.

Anyway, on first ride the clutch is slipping now. Cable free play and actuation point seem to be in spec -- but it still slips and showed no previous instance of slipping before this latest rebuild.

The actuating lever (on the engine) has free play too. HOWEVER, could this still be a clutch disc spacer issue (too many/too thick) regardless of everything else appearing normal?

I hope it's just a solvable mechanical issue and not one of those spooky things (like the countershafts) only an exorcist can remedy.

Any thoughts or encouragement before I open it up again?

Thanks Guys!

[givergas]

when the bike is sitting on a stand with the rear wheel up does the rear wheel spin easy as in no drag in any gears? i can see your engine having some kind of drag in it and the back wheel / chain using the sprocket to bang the crap out of the splines, ......my mind is a terrible thing sometimes......albert

[Darrell]

Sorry about the bad language in the subject line...

There was a perfectly rational explanation for the clutch slipping after all: an extra .5mm clutch disc spacer. No voodoo involved as with the shearing countershafts (Albert, the wheel does turn without any undue resistance).

Configuring the spacer discs to reduce free play to 5/32" on the actuating arm resulted in partly disengaged clutch (don't ask me how or why though). Reducing the stack thickness from 1.4mm to .9mm let the clutch do its job.

[bobwhitman]

DO
Will we get to see you @ HD’22 next month?
Bob

[Darrell]

Bob, HD 22 is on my to-do list. I was one of the first to sign on for the Bad Rock Ride.

Darrell

[Bullfrog]

Darrell,

I occasionally drift off to sleep musing about what the heck could be causing your repeated contershaft spline failures. Still with no real brain-storms.

Question: Are your rear hub cushions and your chain tensioner in good working order?

Ed

[Darrell]

Darrell,

I occasionally drift off to sleep musing about what the heck could be causing your repeated contershaft spline failures. Still with no real brain-storms.

Question: Are your rear hub cushions and your chain tensioner in good working order?

Ed

Thanks Ed, at least the problem seems to be putting you to sleep -- better than losing sleep over it!

And yes, the hub cushions and chain tensioner are good. There's also that nylon upper rubbing block that was showing some wear so I just replaced it with a new one

This time I sourced an "experienced" countershaft from a late production 70A that had over 6,000 miles and (so far) showing no evidence of spline damage or shearing. My bike is is number 180 in the Model 70 production I've considered the possibility of improper hardening of first-run countershafts. That's all I can think of anyway, but haven't taken them for a Rockwell hardness analysis to test that theory.

Darrell