About 15000 miles on most of the parts. It's a 2014, I drove it about 60 miles a day for about 2 years, and it did great all that time. I've derestricted the cdi, took the little governing washer out of the carburetor, and had the dealer replace the jet pin. But I've never done anything with the exhaust or had the valves adjusted. Could either of those be the issue?