650 head on 750

i have a KZ700 engine with a 750 jug cut to 810, I took my GPZ750 cylinder head to the machine shop told them to cut it to the 45 degree seat or about .030, well he cut it .015 and said thats all he could cut, that his miller had a cutter that would get destroyed by cutting the seat any farther, and if I wanted anymore off the finish would not be nice for a good seal, ,015 isn't going to satisfy me, he said take the cometic gasket apart and remove the shim, but at 60 bucks a shot I don't know if I want to do that, now I have a 650 head(81) been cut .025 and some cams a little bigger than the GPZs (365 lift) with more duration, Here's the questions, with a port job the 650 head should flow more and compression will be super, what will the 2mm diference in valve size cost me in performance, and can I cut the seats in the 650 head 2mm without replacing with 750 seats

You could take the head to a different shop and see if they will finish the job. I know the local motorcycle machinist cut a GPz750 head .025" for another guy, and he uses a flycutter that he made and a brazed carbide bit.

Otherwise, it seems like it will take a significant amount of work to make a 650 head flow like a 750 head.

Well I am going to see about another shop, just exploring my possablities,I have been using this particular shop for everything scince christ was a corporal and I can usually get just what I want, everything is all set except for the head surface, I will be riding this one in the spring, 5 years in the making.

agawam wrote:

Well I am going to see about another shop, just exploring my possablities,I have been using this particular shop for everything scince christ was a corporal and I can usually get just what I want, everything is all set except for the head surface, I will be riding this one in the spring, 5 years in the making.

i have nothing to add here except "christ was a corporal" is funny as a f%^$....carry on............