- Location
- North Carolina
Since you probably already have the head off the 650. Shave .030 off and put it back together. May be able to take more off depending on your squish clearance. I took .050 off a old kawi head and got the compression I wanted without the price tag ran like a champ for years. Still does but I sold it. I don't see why you can't do the same with the Yamaha but others can chime in here.
