it wont start?

i agree either valve clearances or crappy piston rings i have bought and sold a few of these and they have useless piston rings that lose their temper and go weak.does it smoke when it was running?i can tell you that if you need a new piston and a rebore use a yamaha t80 townmate piston as this is what they use even though its a 90 its the same piston(believe me)they are a longer stroke than a t80.

adam bike doctor
May 2010

tappet clearances are too tight

m
May 2010

now these are chinese and reading this forum for a while I know that they use soft metal on the valves. They tighten and you may well need to adjust them.
I would also take plug out and pop a bit of fuel in the bore hole and then put plug in. See if this fires the engine. If this does for a short time it would suggest that its a petrol issue.
One other thing when did you last check your engine oil?

bb
May 2010