i bought a 1987 cr250 about 2 or 3 months ago for $200, it came with no tires/rims. it came with a brand new wiseco piston. stock size. and the cylinder was just re sleved. i could see that there was machine work done and the piston was still in the box. when i put it all together i put the arow on the piston facing the exhaust side and put all new gaskets in. i mixed a gallon of 36-1 and kicked it over. it started within 10 kicks. i was thinking it was suposed to start within 2 kicks. but im not sure. once it started i gave it a little gas and it was smoking. then i turned it off. ever since then it wont start. all it does is backfire. can anyone help me. i really want to get this thing running right.