either the rocker arms or cam is knocking, it only happens at high rpms.

 

are you sure its not the valves? real high pitched tapping sound

 

Have you ever had the valve lash adjusted? It needs to be done once in a while. It could also be detonation or carbon buildup. We used to have that alot in older cars before Fuel injection etc. Believe it or not, you could have enough carbon build up that it is knocking everytime the piston hits top dead center.

 

it only does it at high rpm, the engine had been blown up and i just rebuilt it, it has done this before, i swithched the cam and rocker arms and it stopped for about 2hrs.

 

the head had been setting for a while when i picked it up

 

Did you use a new timing chain?

 

no

 

I think its valve clatter. Try to readjust them. How many tanks have you run through the bike since the rebuild?

 

2

 

I would readjust the valves bro.