hey i cant get my bike to start. i got a cam chain 3/4 pitch an put i in. i used the clymer book doing this. got it all back together and it wont start. the timing is dead on. i got fuel and sprk. i think my valve lash is out. the tightest one checks .5mm. would ths cause it not to start? but the thing is i never touched the buckets or the shims. what could possibly keep it from running?