I have a 94 Tomos Sprint. It has new points, new plug, and a few other new parts- It runs great, starts first try every single time. My husband is a 250 pound man, but it gets him to 30mph.
But, when at full throttle, he notices that it would slow down, then speed up- this is a difference of maybe 2 mph- 2 mph faster, then 2 mph slower. But, when he drives it at a slower speed, such as 20 mph, it stays even and doesn't jerk.
I would assume that it's a soft sieze and the head/cylinder is too hot? If that's the case, how do I correct the problem? Add a little more oil? Thanks!