Tdc

dial indicator .............

I'm not familiar with the Hondas. Can you change the indexing of the cam and its sprocket? Generally, there is a mark on the cam sprocket to align with some feature on the head (flat deck, pointer mark, etc.) while aligning an indicator on the crank to a mark on the case. There's only one time in the four strokes that both of these marks will line up. The cam turns only once for every two revolutions of the crank. Don't forget that the cam chain tensioner will slightly affect how the marks line up as well. On Yamahas, you really have no doubt when you're off even one tooth. The mark on either the cam or the crank won't even be close enough to be considered correctly aligned. I would think that if your cam sprocket has a definite index to the cam (can only be installed one way) and your marks are aligned, you are there. If you rotate the crank one revolution from this position, you'll find the cam turning 1/2 revolution and the valves will be in an open position of some sort.

i see your concern. if you take the cam(s) out and then moved the crank you'll need to index TDC using the mark on the flywheel.

well tdc on the comp. strok will be when all the valves r closed on the ex. stroke the exhaused valves will be open

If the cams are out, just run the piston to the top of the stroke and line-up the mark on the flywheel. With the cams out (or head off), every revolution is TDC.