Help, my bike has just started making knocking noise in the engine somewhere, the noise is like a wood pecker tapping in the lump.

this noise only appears around 3500rpm when there is a load on the engine (riding it) then continues up to 6000rpm, where it then teaters off a little.

Any suggestions please

 

Sounds like a valve problem.........
but could be any one of a number of things, including a bearing.....I hope not !

 

check your cam chain. they loosen after time and slap at hi revs
tachyon