I just had the head on my Yamaha Warrior done and I put in Kibblewhite valves, springs, retainers, etc... When I did I had the valve seats done at a machine shop to match the valves to the seats. This is really the best way to go to make sure the valves seal properly.
2008 700XX - OMF Beadlocks w/Billet Centers & Reinforcement Rings, Kenda Kutters, CCP Steering Stabilizer, ASV F3 Levers, ODI Rouge lock-on grips, Houser Bounce Nerf Bars, Pro Armor skid pad, UNI Filter
2007 400EX - CCP Steering Stabilizer, GT Thunder 450R Shocks, 450R Rear Brake Conversion, YFZ450 Front Brake Conversion, ProTaper Bars, Rath Racing Nerf Bars, Alba Elite Bumper, ASV F3 Levers, ODI Rouge lock-on grips, UNI Filter, Kenda Kutters, Pro Armor skid pad, Armadillo Swing Arm skid pad