Pulled the exh.. no go. Using the elec start, I get a spark but with prolonged cranking, the spark gets erratic, then disappears completely. Let it sit, try again, I get spark then slowly goes away.... Grounds and the bar switch are next I guess.. UGHHHHHH

 

I had a moto 4 80 drive me nuts like this. Eventually picked up a adjustable spark gap tester and noticed the spark was always weak. It would push start ok cold, usually start fine once warm but not always. Spark would only jump 1/4" in the gap tester. My XR70 would jump 1/2 to 5/8". I ohmed the coils under the flywheel and the resistance spec was way off. Replaced those and the spark became way stronger and would jump 1/2" gap just fine. Little guy started good after that on the starter and never pushed it again.

 

This is exactly the page i have been looking for! Did anyone find anything out to fix this? I have exactly the same issue as the poster. I am racking my brain trying to get this thing going. i cleaned up every connection in the start path and there was no difference. i have a good ground to everything electrical. coil, regulator, and killswitch have been replaced-all of which have been tested and are in working order.

 

I had the same issue on 1 of our 200's I switched the cdi box from my running one to the non and ran like a top It had a brand new mr electric one on it ended up getting an OEM one off ebay runs great now

 

The non running one had week and inconsistent spark