i put a new piston in my sons trx 70 and am trying to set the timing,i lindes up the 0 mark on the cam sprocket with thw notch on the head and i put the flywheel on the "t".should it be on the "t" or the "f",it seems to have compression just wont start.

 

Yes you line up the " T " .. The " F " is for ignition timing..