96 1100 venture shutting down

My 96 1100 Venture with 180 hrs that has had no problems since purchased shuts down after 15 min of 35 - 40 mph cruising. Then after 10-15 min it will start up again and the same condition re-occurs. I brought it to one repair center who did not want to investigate and another mechanic states the crank shaft is warped.

My guess is the power pack could be the cause. Does anyone have any knowledge on this condition.