I have a 1600 twin port that has had the heads machined , can some one please tell me .At what depth of a stock head you need to fit copper head spacers .


The measurement of depth of a stock head is ?

cheers seagull

mine measure 12mm from the flat to the seat ,stock

there not all the same but u can go to about 14mm before u run into clearance issues with the top fin.
Top fin can be skimmed to clear or a spacer ring can be used,
compression ratio now thats another issue to think about.

as jj said.

The more you cut you then need to "cc" the heads.

Can get tricky once you have taken away all the easy bits of the head and opend them up.

"most" heads seem to be round the 50cc mark - but you can get them to work either side of this.

I am thinking of valve clearance & valve adjustment as well