hey guys, I think I know how to fix that seat on the 91.

to make a tool to cut the seat on the lathe, turn down some drill rod with a step on it, the small end will fit deeply into the intake port from the inside of the cylinder, and the step will have the correct angle cut in it for the seat. then (carefully) use course valve grinding compound to cut the seat, then once the seat is cut use a fine compound to hone the seat smooth.

my problems are.
1) I have turned drill rod on my lathe before, but it was pretty hard on my lathe.
2) I really do not have the correct cutter for this job.
3) even if I knew the correct degree of angle I need for the seat I don't think I can cut it accurately on the drill rod with the lathe.

Jim