Lanny,
I had a similar condition on an old BMW. It was suffering from the hairline crack syndrome. Once the bike warmed up, the coil started to discharge itself onto the GAS tank
But before you replace anything, you really should test it. The Haynes manual will guide you, all you need is a cheap multimeter from Radio Shack or Sears. I'd also warm up the coil with a hairdryer to see if that has any effect on internal resistances.
I'd also check your air and fuel filters. A clogged up air filter will make the bike run a little rich, not a big deal when cold, but will become noticable when warm.
The crank sensor is easy to check. Just measure the resistance using your multimeter, and compare with specs in the manual. BTW BMW wanted $600 for my old R65. Fortunately I found a retired elec. engineer who rebuilt mine for $120.
The ignitor may not be so easy. Back in the 80s, a few simple resistance measurements would tip you off, but todays ignitors are too complex for this approach. The dealership may have a scan tool to help you out, or you might be able to find another America rider in your locality who will let you borrow theirs for a few minutes to see if that helps.
I'd also also check your gas tank vent. Run the engine until she starts to stumble, then open your gas tank cap. If you hear air rushing into the tank and/or the bike starts to run well again, your vent line is probably clogged.
These intermittant problems are most fustrating. Take your time, you'll eventually figure it out. When you get really PO, take a break. Kicking the bike will not help ... I've tried this approach and it doesn't work!
Good luck with it
JohnB
