I have a 1985 atc200x motor im replacing the top end gaskets i removed the whole top end. now i set the whole thing back together. i want to know how the camshaft has to be set. this is the way im doing it im setting the piston to top dead center and i put the cam back on, then i put in the cdi pulse unit on to set the cam. i put the cdi on the fireing mark. so the engine is actually in combustion point. so am i doing it the correct way? or is there another way. please help. would apreciate it alot.

85 ATC200X motor

 

Sounds like you have it correct to me.

Lobes down and the pin to locate the advancer is about at the 10-11 o'clock postion.
This will put the mark on the advancer rotor at 12 o'clock at TDC.