Worn-out starter clutch

E

eabergman

Full member
Checking some things on my 1971 750SF, I discovered the starter clutch was in need of service, maybe replacement. In particular the surface of the freewheel sprocket that engages with the rollers shows evidence of a hard life: discoloration from excess heat and lots of dings. The rollers are all in one piece but probably due for replacement as well. My question is, can the freewheel sprocket be reconditioned in any way? For example by skimming on a lathe and re-hardening. Or by cutting it down and shrinking on a new bearing surface. The starter has always worked fine on this bike, with near-instant starts. It was not making any scary noises or slipping. But it's pretty clear that was going to change soon.
 
Shrinking on a new bearing surface has always failed miserably... the forces applied to the surface during the starting procedure are enormous.  The surface can however be skimmed slightly, smallish dings don't have much effect on the clutch function.  Rollers, plungers and springs are available from all the usual suspects.  Check the inner ramp thingy for damage, very often these are cracked and can cause problems.  Not really easy for the average DIYer to swap, but replacements are available if needed.

piet
 
I wouldn't worry Eric.
Run it into the ground. We'll all be dead by then.
If that fails, replacement is easy.
Best regards
Paul
 
Piet, Paul,

My machinist skimmed the bearing surface with a diamond-tipped cutting tool. He took about 0.006" (.15 mm) which cleaned the surface almost completely. It may be a little while before I can try it, as I am waiting for some other parts from Wolfgang, but I'll report on it when I do.

Eric
 
The Back Plate has to be pounded flat an firmly attached to the Fly Wheel - Tig weld or spend more money tapping and screwing it tight.

You don't want to rattle them dogs - The original Breganzie Rivets are JUNK.

Other then that, I adore, with fond memories, a pretty girl pushing my Breganzie, at sun rise, to get to work.
 
  I shrunk on a hardened inner ring (IR) from a needle roller bearing  after skimming the freewheel sprocket, but I also tacked it to the freewheel with 2 large arc welds - this has been on my own bike for nearly 30 years and shows no signs of wear or loosening. - Regards - Phil
 
Shrinking on a new bearing surface has always failed miserably... the forces applied to the surface during the starting procedure are enormous. 
phil37 said:
  I shrunk on a hardened inner ring (IR) from a needle roller bearing  after skimming the freewheel sprocket, but I also tacked it to the freewheel with 2 large arc welds - this has been on my own bike for nearly 30 years and shows no signs of wear or loosening. - Regards - Phil
Click to expand...

Conflicting data from you both, Phil and Piet??
 
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