wont start

[sportracer07]

Ok guys i just put my 06 yfz back together after installing a new head gasket and base gasket, i have checked the timing 4 or 5 times now, and i have spark and fuel, it doesnt backfire or anything just cranks, what did i do wrong

[sportracer07]

Ok i figured out that i have no compression so i tore it backdown only to find nothing wrong, rings are fine, headgasket and everything looked good what could possibly be wrong?????????????????????

[aaamx]

check your valve clearance