Originally Posted by jesusgatos
200hrs and 8500 miles on this topend. Robo rode Vegas to Reno right after we built it and afterwards it's been ridden almost exclusively on-road, lots of high-speed backroads and highway miles. Oil changed every 1000-1500 miles. Valves never moved after first adjustment. Bike was still running great
, but suddenly started burning oil, so pulled it apart to take a look. Had ordered some rings and valve seals, but wasn't planning on replacing the piston. Robo ran one of his EXC's to 350hrs without doing anything more than changing the oil, and he rode that bike HARD. That's what finally convinced me to sell my XRR and replace it with a KTM. We put a new Wossner piston in this 450XCW right after I got it and figured I'd be able to pile on the miles without worry, especially considering how I was riding it. And it's been rock-solid, but take a look at what I found when I pulled the piston. Lucky-mo-fuckee, right? Cylinder and piston skirts still look great. So do the valves and valve-seats. But looks like I'm going to have to break down and order a new piston. Damn these high-maintenance machines!
Hmmmmm, I wonder if a stock piston would last longer? Bob of Ironmandualsport tried a Thumper 570 kit,put about 25 hours on it and the piston cracked right down the middle in line with the wrist pin,way out in the middle of nowhere in Nevada. It went from running great to dead in about a mile. That was on a 07 525 though.
Its nice you caught this quick like.