85 big red losing spark

[mike m]

Hi I bought this big red a few months ago, it was a half torn apart pile, been slowly piecing it back together, it was a big fight to this running again anyways after it runs for 5-10 minutes it starts popping thru the exhaust and shuts down. when it cools off starts right up again? then does the same thing. I've already swapped cdi s could it my coil or pulse generator, has anybody ever had this problem before. any help would be help full. thanks mike

[Russell 350X]

Sounds like the coil is bad.

[tri again]

If it seems heat related, I'd hit components one at a time with a hair dryer
when you are sure it will start.
Sometimes compressed air is enough to cool stuff down to a workable temp too.
Pls let us know what you find.
Thanks