As the engine turns over there is a very pronounced "click" from the kick start mechanism.

Its the ratchet mechanism clicking, like when the kick start returns.

My question is, this seems a bit harsh, surely the bike will sound like a football clacker when it runs?

I'm pretty sure I have rebuilt the engine properly, the kick start shaft is in the exact same place as it was before, but I didn't test it.

Do I have to strip the whole lot down again to change something? A common issue?

 

Edited to add: Sherpa 250 T 1978

Edited July 6, 20188 yr by yamanx

Hi, there is a thin shim like thrust washer that goes on after the 28 tooth gear is assembled. It is often missing on the motors I have worked on. The noise you can hear could be the starter shaft moving sideways a bit. Just to mention, these days I make my own shim, usually out of a piece of stainless. I have quite a stock of various thicknesses of stainless from for example, an old butter dish, flat part of a sink top etc: Each build needs enough clearance for expansion, but not too tight as well. Was the bronze bush badly worn ? If so the gear could be kicking sideways a bit. One other thing to consider. Oil. Avoid at all costs GL5 gear oil. It contains additatives that will eat yellow metals, that is bronze or copper based. GL4 mineral oil such as Comma 80-90 should be o.k. Mostly I use Millers Green gearbox oil which is fine. Hope this helps, John.

 

The kickstart shaft and the return stop for the kickstart shaft needs to be set up so that the return stop holds the ratchet teeth apart. Some people accidentally leave out the shim that johnjsy is talking about and the ratchet teeth may not fully disengage. This MAY be the cause of your noise

Another possibility is that maybe there was a problem with the return stop or the shim was missing before you rebuilt the motor. You didn't say what the history of the motor was so I have no idea if this is likely or not. I know that I have discovered many mangled kickstart return stops and kickstart shaft shims missing when disassembling 5 speed Bultaco motors.

Thanks for your help guys.

Just fitting the kick start itself seemed to cure the issue, probably because it slightly holds the shaft out?

 

Anyway all seems good to go