After 14 years and 15,560 miles my wife's 'O4 rev finally took out a piston. Mind you it still ran, so we rode it back to the truck 40 miles and 60+ MPH. (that's my wife taking it easy on a broken motor). I was hoping it would go to 20,000. But I guess I will have to open it up for the first time. This sled has been pretty bulletproof, gotta love the carb 600. Couple new slugs and run it another 15,000!