well tomos have NO points! it's all electronicaly controlled.well exept for older models of the a3 engine. it might be the carb. turn the bike on and run your hands down the pipe. (be VERY VERY careful not to touch the pipe it is extremly hot!!! i would know i've burnt my leg twice and my hands once) if you feel air coming out there is a hole. then if there is none put your hands by the cylinder where the pipe meets the head. if exaust comes out there then it is leaking. also another way to check for leaks is stuff a rag in the end of the pipe and it should leak out the big circle thing in the back. if it leaks out the cylinder too then there is a leak up there. tighten your bolts. if it lkeaks anywhere alse weld it.
hope this helps
ps if it is not the pipe it is the piston getting too small in the cylinder or the cylinder widening. this is very very bad. u will need a new cylinder or piston or both.