Andy,

You will know the TDC for combustion because that is the stroke that will have compression. The other TDC will not have compression. When I did my engine, the little dot on the camshaft came in at 6 o'clock rather than the 12 o'clock as this picture shows from W8YE. In either case the dot has to be 1 tooth before 6 or 12 o'clock, which also happens to fall on the imaginary red line shown in the picture from W8YE.

It actually turned out to be easier than I expected.

Thanks for the explanation but how do you move the gear on the shaft? Does it just lift off of the shaft?

After you take the cam cover off, if I remember correctly, you have to remove the valve cover, rocker arms, and pushrods. Then the cam slides out, move it to the correct position and push it back in. For my Magnum 52 RFS, the cam gear was 1 tooth off. I pulled the cam out, turned it 1 gear, and then pushed it back in.

Then you can put the pushrods back in, screw the rocker arms back on, and finally the valve cover. I think that if you only unbolt the rocker arms without touching the gap adjustment screws, you won't have to do the gap adjustments. But in my case, I had been running-in the engine and the manual calls for a gap readjustment after running the engine for the first few hours. My engine needed the readjustment after those few hours of initial use.

This exercise really helped me understand the 4-strokes better and build up some confidence in them.

The gear teeth are helical so when you pull out the cam it will twist.

The cam will twist when you attempt to re-install it, so you must lead the desired position upon installation.

When the engine is at actual top dead center on the compression stroke, the cam mark will be down.

But you can re-install the mark in alignment with the cam follower hole which is more accurate. The cam rotates half the speed of the crankshaft. So if you then turn the crankshaft one full turn, the cam mark will be down with the crankshaft at top dead center.

Thank you all for your help!!!
Andy