2007 grizzly 660 860 km yes km. I have had this bike since new and rarely drive it mainly because it doesn’t run right. After about a year old it started to lack power and bog when in the mud. Thought it was the carb cleaned really thorough several times. Still didn’t run right. Bought a jet kit and striped a jet trying to get it out. So I bought a aftermarket carb, installed it it without the jet kit. started up idles really good drives without missing no backfire. Just now the bike has no low end or top end. Top speed is 55 60 if I have a long enough straight stretch. New plug, spark seems good. Cleaned the clutch new belt. Cleaned the tank, new fuel before the carb change. Checked the valves at about 500 km around when I first started having troubles. I don’t know if it’s the after market carb that’s the problem now. Should I drill out the air fuel plug and Adjust that. Or is it something else I’m missing. I’m going to buy a compression tester tomorrow and check that. Maybe check the valves again but I doubt it would cause that much power loss. I have a 250 yam that has more power than the grizz.