Self tightening primary chain

Previously gary_hawksworth wrote:gary...i,ve had the same problem on my single.... i take it the bike has a dolls head gearbox ?..when adjusting the primery chain pull the gearbox back using the adjuster until the chain is on the tight side....then using the adjuster nut push the gearbox forward until the chain is adjusted correctly.. then tighten both bolts.i,ve found it importent that the adjuster bolt supports the gearbox from being pulled by the drive chain.i,ve found there is loads of play at the adjuster bolt between forward and backward movement..used this method for years without any problems...tony

My primary chain appears to tighen its self on my 1938 model 50. I have tightend the top and bottom fixings on the gear box. Any ideas why it should do this? Should there be some king of locknut on the adjuster? If so I can't see how it can be fitted as the retainer plate would seem to stop it.

Any ideas?

Gary

I can second Anthony's solution. Make sure the adjuster is pushing the box forward when tightened. My chain was tightening every ride until I started doing this. Seems ok now