Today I went to ride my 2001 CR 250 and it has lost all it's power. The power loss is most noticeable in the bottom to mid range. I checked the spark plug and it had grey deposits all over it. I put a new spark plug in it and it was still powerless. I have about 40 hrs on it since it was new. Before this I have been fouling spark plugs like crazy. I run premium pump gas with Castrol oil at 38:1. I clean my air filter and change the bottom end oil religously and the bike has run great right up to today. what the heck could be wrong? :(