Had primary open to install new adjuster and when measuring slack at one point it was fairly tight, rotate motor and slacked increased. Is chain stretched or another issue. Thanks.

 

Having a difference in chain slack as you rotate the chain around is not unusual, but can there be too much of a difference - yes, just read about a scissored crank that had that issue. If you are worried maybe check your crank run out, but if it is only 1/8" or so then I would not worry.

 

Is "runout" rotational or in and out movement?

 

It is how "out of round"(rotationally) your crank is. In and out movement would be "end play". To check your crank run out you will need to open up your cam side cover and remove the cam plate, then using a mounted dial gauge or a specific tool like Fueling makes (~ $100) you can get a reading while you rotate the back tire in 5th or 6th gear.

 

Is there any way to check with a dial indicator with a mighty mag attachment? I'm thinking there will be nothing to attach mighty mag to.

 

Not sure about the magnetic base, but I bet you could use some C-clamps or something similar to hold the base steady.

 

Yes, could absolutely do it with any indicator and any magnetic base. Just as long as you can hold the indicator solidly and put the tip on the crank to get a reading. If you're a machinist then you should understand, it's just like checking runout on anything. It doesn't matter how you hold the indicator, nor does it have to be a linear travel indicator. It can be a test indicator like a Brown and Sharp Bestest. You'll get a reading regardless.
If there's nothing steel to put the magnet on just clamp it to something.