Dear 450 XCW Motor.   I am sorry for the trouble I have caused you. ( 2016 MY - Purchased Aug. 2015 ) ( Edit )  Oct 4. )  My new strategy is to replace piston?rings at 250 hrs. ) ( Edit }  Oct 21 )    To Wrap Up this discussion ( attempt )  : Ask Mr. Piston -     We had such a good relationship, Why did you break-up? A. We had been together too long, I just wore down. B. That gas you fed me, made me throw-up C. I left you notes, in the form of oil in the intake tube, You chose not to read them.   Remember that Tim Dunaway old me the piston would have passed inspection one hour before failure  The gas was probably 3 months old.  What an idiot.  I now own a bottle of Sta-bil The motor oil in the air filter box was definitely there at the failure. Subsequent Leak Down was Zero pressure. The top of the piston and the valves were very clean, so I am somewhat doubtful that the motor was really pushing oil into the intake before failure. I will definitely be checking this going forward. Thanks to you all for your contributions to this discussion.  I am planning on the following the advice of a trusted public servant and " Getting Over It". P.S. copying this last comment to the first post in hope that it may save someone reading all this.  Evidently your life has been harder than I imagined. 315 hours of Sand Washes and Sand Hills was too much for you to bear.  September 26, four of we desert roamers where finishing an Excellent run of about 65 miles in rare soil conditions. Truckhaven to Inspiration Wash, 5-6th gear application:  Mmmm something does not feel right. Not holding power in 6th, try 5th, mmm. Rolling to a stop in a cloud of blue smoke. Now I know that is not a good outcome. Geez, I though this motor was good for 10,000 miles. When the team assembled for the diagnosis: fuel pump is good, motor cranks, appears to have water and oil. But wait, SoCalMule notes leaking oil at the air filter.Oh that is just a messy filter. On closer inspection, no something much more sinister.  The group agreed that half a cup of motor oil in the filter box is a grim situation.  I have heard good reports ( Mark ) about SDPowerHouse on Old Highway 80, Flynn Springs. Well Hell, I will just stop by and have a chat.  I was impressed by the shops' order and the staff; Tim Dunaway and assistant Bob. Yeah, could be cracked piston and or ring. 315 hrs is about what you expect running desert conditions 90% of the time. " Did I mention I was using 3 month old gas down that sand wash?"  Yes that can cause micro pre-detonation you might not hear which is hard on the motor.  Dang, that falls into the What a fool am I category. Really, take the trouble of cleaning the injector and then run old gas.   After deciding to leave the bike, I heard that Tim works on all of Chilly Whites bikes.  That sealed the deal for me. Next week Leak Down Test. Then we go from there; cylinder, piston, oh heck think about the valves as well while it is apart. The calendar is marked at a 3 week repair estimate;  see you guys at the end of October with my New Motor.        Bagstr