CB200

[Johnwebley]

   how can I check if the nearly 50 yearold capacitor is OK,?

slight sparking at points ,

only one set,uses wasted spark system ,

  miss fire at higher revs ,

get worse when hot ,

advice needed

[K2-K6]

I don't readily know this John, but link seems a competent approach https://www.hunker.com/12226169/how-to-test-a-condenser-in-a-small-engine and may help you.

If the points are at maximum gap it may affect the misfire as minimal gap in specification will increase the dwell and give best chance of coil saturation at highest rpm, may be worthwhile trying first to see what effect it may have.

Same with plugs regarding gap too.