I have a friend who owns a yamaha blaster 200cc. I put a big bore 250cc kit and rebuilt the lower end as well. The kit recomended some jetting, tried it.. And it was horrible.. it was clean on top, but was way to rich in the bottom end. I dont know the jetting that was put in there.. I know the infor isn't that clear. He rides at around 3500 to 4500 foot elevation. Any idea's???