1989 yz 80

I've finally met my match on this one. After replacing the source and ignition coild on '89 yz 80 I still can't get it to run. Top end is fresh, carb clean, air filter clean. Ignition system checks out per the factory manual. Spark seems good but occasionally intermittent (sometimes you can kick it 12 times and get 12 sparks, other times 10 kicks gives you 1 spark). Is there anyway to test the CDI black box short of buying a new one. I have nothing left to try.

Having trouble diagnosing an ignition problem with yz-80. Does anyone have a way to test the CDI? I've gone through all the steps in the shop manual and can't find any other components that are not within spec. Carb is clean, air filter clean, plug is wet, no pop but intermittent spark (sometimes consistent, sometimes misses numerous revolutions). I've never been stumped like this before.