gy6 timing marks

[zman007007]

I want to make sure I am using the right mark to get TDC. I am asuming the little tab in the pics on the left is where I need to align my timing mark on the flywheel. Right? Which of the marks on the flywheel should I use. thanks

[xlint89]

Mine is right about your third pic, but you should actually make your own mark. Make sure your piston is at TDC by looking with the head off, or use a straw or something through the spark plug hole to verify it's at TDC then make your own mark for future reference. The Chinese quality controls suck, so don't rely on the flywheel marks.

[zman007007]

so it doesnt matter which stroke it is on?

[xlint89]

When timing the cam, you want both valves closed with piston at TDC.

[ckau]

I use the ROLL OVER METHOD
This is good to use if your not sure if the piston is at TDC [top dead center] or the timing marks on the fly wheel don’t line up with cam position, they rarely do!
This also takes in to account cam chain stretch ,worn cam lobes, cam gear or rockers especially in older motors with a lot of hours.
Remove spark plug. This make turning the motor over easy.
Rotate the motor CLOCKWISE at the flywheel.
Watch the rockers go through the cycle
Stop rotating when the INTAKE valve, the top one, is all the way open, rocker has pushed valve completely down.
In this position ,adjust the EXHAUST valve. Loosen the locking nut [9mm] and with a slightly oiled feeler gauge set the gap to whatever your motor spec. manual suggests.
Tighten locking nut and recheck for proper setting.
Again , rotate motor CLOCKWISE until EXHAUST valve is completely open, Rocker is fully down
Set gap on INTAKE valve
Tighten locking nut and recheck setting
Rotate motor through cycle again and confirm both settings.

[zman007007]

now one says 1 valve open and 1 closed, I too also always heard both closed. I have rebuilt car engines, chain saw engines, lawn mower engines and old Harley Davidson golf cart engines on which I split the case to do so. So I guess I will just do it just the way I have done those. hit and miss, till I GET IT RIGHT. LOL

[SLESTAK75]

Mine is tdc at the top of the little arrow in the rectangular mark. Just do like x said and the n make your own mark. It only matters which stroke AFTER the cam is installed. If you are installing the cam then just get it to top dead center.

[xlint89]

Actually Ckau way does work very well too.

[zman007007]

cool thanks for all the help

[Masteryota]

Originally Posted by zman007007

now one says 1 valve open and 1 closed, I too also always heard both closed. I have rebuilt car engines, chain saw engines, lawn mower engines and old Harley Davidson golf cart engines on which I split the case to do so. So I guess I will just do it just the way I have done those. hit and miss, till I GET IT RIGHT. LOL

Problem is, you can only be so far out of time before you start having interference, so try for a hit the first time, everytime, lol.