Okay, now that we know the engine is turning over slowly, it really only is limited by a few things. As we are sure there is a fully charged battery turning over the new starter, we have to assume the starter is good and the power to the starter is good. Now the next step is to check the engine timing to ensure it has not skipped a tooth on the cam gear. You have already checked the valve clearance at
0.08 ~ 0.12 mm
(0.0031 ~ 0.0047 in)
0.12 ~ 0.15 mm
(0.0047 ~ 0.0059 in)
So if these numbers are good, then its time to check the engine timing. Put the flywheel at top dead center. you want to get the marks to look like this:
remove this cover to inspect the timing marks
it could also look like the image below
Wrench to counterclockwise rotation
Align the “I” mark ① on the rotor with the
stationary pointer ② on the A.C. magneto
cover. When the “I” mark is aligned with the
stationary pointer, the piston is at the Top
Dead Center (TDC).
make sure the mark on the cam gear is pointing straight up and lined up with the mark on the head as in the picture above.
then adjust your valve clearance. This will ensure your timing is correct and that the cam has not jumped a tooth, putting your valve timing incorrectly