Wow at least you got the attitude to win ! I don't have to wait till spring Im going to run it stock first then see how I can improve it the engine was built by Houser Racing when I got it.. I forgot to add that the low and high speed jets on those carbs are/were adjustable . So yes you better know what and when to adjust it ! I have worked on a lot of 2 strokes but never a Blaster ATV but Im sure that I will figure it out and may be good as you one day . .. not an insult either.So you are going to use this junk mikuni cause you need to wait till spring to install the keihin and jet it correctly. So keihin expert. What does spring have to do with anything. Did you ever play with jetting when you raced these big events that had temp changes, elevations, etc? Why does it matter when you jet it? A true racer will tune and tune and tune to keep it going strong. Theres alot more to winning than a carb thats "special" from the factory. BTW Nah I don't race or anything competitively. I just build stuff to stare at and act like I have experience. Good luck chasing hp out of your carb. Nuff said. I'm out.