An update: Still no luck fixing the delayed stalling problem.
Replaced the bystarter, coil, spark plug, air filter, cleaned the idle jets in the carb. No luck. Tried premium gas, riding w/ the gas cap off... no luck.
Next we are replacing the float bowl.
Frustrating in that after 6 miles riding, the bike will stall out - sometimes at the same street corner! After sitting 5 minutes, it starts right up. Weather isn't a factor.
I haven't heard the fan run in this year. Could this be a problem?