My son is a 16 year old MXer that has been riding since he was 6. He rides hard and is a top 3 Novice in Texas. We had an '04 that had continuos valve issues. We sold it and bought an '06. Ran great for 15-18 hours and then it got a bog when hard landing and in the woops. We have cleaned the carb and checked the valves. It starts easy and runs great on flat ground. I have heard grumblings of problems with the '06 carb but have not seen anything definitive.
Does anyone have a similar problem that has been resolved? If so what was the solution?