I'm new to go kart racing. I built a gx160 with a flat top piston, billet rod,14cc head,methanol carb that is bored,ported head,and a 356 cam. It bogs on the low end takes a half of a lap to get up to speed and starts pulling hard 3/4 way down the straight away. I'm running a 11t clutch and 71 rear gear. I'm going to try a 75 tooth rear but I'm thinking that I might have too big of a cam for the track size. 6250 is the highest rpm I got. A friend drove it and felt the low end bog but it performed better for him. I weigh around 260 and I have 100lbs on him. Looking for some sound advice besides loose weigh lol..