I have a 2 stroke yamaha 90 with hydrotec heads, they appear to be milled about .125 what is the max that I can mill without hitting water jackets. I want some more compression.

The other questions

I have the hydrotec heads and boyson reeds, and 165 jets. It seems flat at the top end. What jetting would you have thought??

What max spark do you recommend.

I am running 100 octane.

I have been running 3.0 loopers for the last decade and don't have a good feel for the smaller engines. I have it on a avon Rib using it for sport and skiing.