Picked up an 01 Trailblazer to fix up for the kids. Oil injection is blocked off so I have to premix and the carb was crap so I bought a 34mm Mikuni to replace the stock 30mm. Needs a slight bore, stock piston is right at service level with 115lb compression so I'm putting in a new 73mm piston. No other mods done. What are the benefits to shaving the head to up the compression? Is it worth it on an otherwise stock bike with a little bigger carb? And last, any suggestions on where to start jetting as far as premix ratio and primary/main jet size, clip position, etc.? I have a 45 pilot and 220 main in the carb now but that's quite the step up from the 30mm Mikuni with a 40 primary and 140 main. Thanks for any help guys!