Had my ds450 since 4-6-08 . Changed oil on it 3 times. just got it back from swingarm bushing recall and flywheel bolt recall dealer changed oil after recall. i drove it about 4 hours and it was losing power power and started knocking its the rod bearing no doubt. all stock.Bringing it in on monday i have the extended war. but this thing is junk i had a 98 banshee in 1998 that i beat for 3 years without a engine failure and this new top of the line 4 stroke barely makes it a year and is half as fast as a two stroke. I bought this four wheeler to last and it let me down.