The CRM has an annoying irregular knocking noise (metallic thud) from near the front. It is more noticeable at low revs (seems louder as the bike tick over is dropped to almost stalling) i dont think it is piston slap as that happens on every stroke(??), and the CRM isn't using excessive oil /petrol.

The noise tends to fade away once the bike is warm, but still occurs occasionally at tickover.

A known problem is the counterweight / shaft bearing on these bikes but i would assume is more regular pattern to the noise?

if the powervalve mech failed could the pv rotate into the path of the piston, or is it machined in such a way that it would never enter the piston bore?

Yo,

The balance shaft can be checked for wear - this has been covered elsewhere on the site. As for anything else im not too sure...your best place to start is to search the site and see what anyone else has come up with...

B.

The PV will always clear the piston,tried it yesterday on my barrel and I had it bored in situ'.
Doesn't leave much m8.
Endz,balancer,bore really...