timing problems

I just put in a hc pistion and new rings and cant get it to run. the bike pops loud when I kick it over and Ive checked the marks on the cam sprocket twice now and cant get them any better and its still popping. I dont know what else to do.

are the valve clearances correct?

yes I checked them every time i took off the valve cover

One tooth off is all it takes... its gotta be spot on

when I was putting everything back together the chain slipped off the gear on the bottom end and I had to take off the case cover and the flywheel to put it back on. when I put it back on I made sure the crank marks were lined up in the hole on the other side of the motor Im debating on taking everything back off and doing it again.

be ur best bet..most likely it moved when you put it over the cam sprocket..

i do believe yur correct on that, just went thru same deal on my fofiddy!

there is a little trick to try, at top dead center you can move the cam by hand very little each way before the piston starts to move enough to make it stiff to turn. your cam should be center of that free play. the cam marks should move about 1/4 inch both ways before it starts to get hard to turn.

there is a little trick to try, at top dead center you can move the cam by hand very little each way before the piston starts to move enough to make it stiff to turn. your cam should be center of that free play. the cam marks should move about 1/4 inch both ways before it starts to get hard to turn.

Yves , welcome to TT , good post ! , I show this trick to guys all the time , its almost as good as putting in a dead stop and finding tdc , and its plenty good to see if your a tooth off :thumbsup:

Yves , welcome to TT , good post ! , I show this trick to guys all the time , its almost as good as putting in a dead stop and finding tdc , and its plenty good to see if your a tooth off :thumbsup:

Thanks, sorry again about last night guys. Really just want to help guys out with there scooters.

and use the marks on the magneto (way more accurate) not the marks on the crank drive gear.

Thanks, sorry again about last night guys. Really just want to help guys out with there scooters.

:thumbsup:

and use the marks on the magneto (way more accurate) not the marks on the crank drive gear.

yep , and you can see the all the marks from one side of the engine that way :thumbsup:

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