I am thinking about switching off Ski-Doo 2-cycle non-synthetic to Amsoil Interceptor Synthetic or similiar. I have 3500 miles on my 2001 MXZ 700. My valves have carbon deposits on them after 1000 miles with the Ski-Doo oil. It works, but I think there is oil that is better. Am I going to have any problems running better oil in my sled at this point? Please advise.