Buddy just got a 440 with 12:1 piston installed and when he gets it into a higher rpm it sounds like the valves are hitting the piston. he took it to the honda shop that put it in and they said it was out or time, so they adjusted the valves and got it in time, it was still tapping when he got it bac, he took it back and then they said it was a leak in the head they put a new gasket on and it still makes the noise, they then supposed to have tore it completely down and checked everything and it still makes the noise.

It doesnt do it at low rpm if you romp on it pretty good it will start maing noise, i mean its the most sickening sound's like you got 2 welding rods beating on a peice of steel

Figured all you honda guru's could help him out, he would appreciate it alot.

 

Are you sure its not the Cam??? What kit do you have in it?? Ive never had anything go wrong with mine, but when I had a defective Cam it madea banign noice sorta(hard to explain) and it was the older style Hot Cam that they changed, once I change that it was fine .
Im not much help, but I do run the 12:1 as well. Good luck

Tina

 

he has the stock cam, but for the kit he just went in there and they punched it out to a 440 and put a high comp piston it.

and its 12.5:1 if that makes any difference