I Might have the same problem, I don't know. I only had the bike about three weeks now, 1996 600 S. But it starts right up runs fine, other then the low rpm jumping. In fact I rode it to Daytona Beach and back, about 90 miles round trip, and it ran great. I might try the carb clean trick of draining the carbs, filling 'em with Cheveron Tachron cleaner and letting 'em sit over night.