Big problem

[83Atc250R]

Ok i am ready to do the rebuild on my 90 motor. I got the plastics, tank, carb, intake, and exhaust off. I am not going to remove the motor but thats not the porblem. The guy who had it before me welded the shifter on so i can get the pull starter off. So i cant find TDC. Is there another way i can do it like is High cam TDC? or can i mark the cam and just put it in that way. I need to know pretty much how to get it out so when i put it back in it will be correct.
Tony

[Fuzzy]

The easy way is to put a screw driver in the spark plug hole and feel for when the piston gets all the way to the top. When it is at tdc set your cam. The worst thing would be if it was on the wrong stroke. It that is the case. Put the screw driver back in. And turn the engine until you feel the piston get to the top again. Then pull your timing chain off. And rotate the engine until the piston comes back up. And then put your chain back on. And you should be set.

[dads]

If you watch your intake valve , when it closes the piston will be coming up on compresion stroke. then do as Fuzzy said. then put a mark on the cam at 12 oclock . when it goes back to gether you have two posisions the crank can be set at , one will be right one will be 180 degrees out.