I took the head off my bike again to redo head gasket and noticed both inlet valves were hitting the pistons. Last time I had the head off I lapped the valves in as the seats were relatively ok. I've now measured the springs and they are all shorter than they should be. Would this weakness cause the valves to make contact with the pistons? I can't see what has changed. The head gasket is the same thickness as the one I took off.
Hi,
Has the engine been run for this to happen? If the springs are too short or weak the valves could bounce and perhaps make contact with the piston but most likely to happen withy the engine running and at more than tick over.
Dave.
have you fitted the pushrods in the correct order?
The only other thing that could cause this is if the camshaft timing is wildly out. at TDC both inlet and exhaust for one cylinder or the other (but not both at same time) should both be open, roughly an equal amount. you can check this with the rocker cover off and a plug tdc tool.
I did ride the bike and didn't notice any noise so am quite surprised that this has happened.