I have a 06 crf250r that I bought about a month. It has about 5-6 hours on it. I have cleaned the air filter after every ride and changed the oil 3 times so far. Now I took it out today and it is running terrible. The engine revs but there is no power at all. Im new to four strokes (had two strokes all my life) but if I had to guess it seems like I blew something in the engine. If that is true I would be very upset since I only rode a few times around my house. I didnt ride it very hard and did the normal maintanance. If you guys have any ideas please let me know.
I had that same type of problem with my two stroke KDX. It ran great, then one day I took it out and it felt like it would rev up like normal but wouldn't get any power to the ground. I took it home and was mad that it was running crappy. I cleaned the air filter, then took it out the next day and it ran fine. I personally think it was the weather (it was cold that day) and it was just acting up. Could this be it for you? Or not?
I cleaned the filter just before riding. I will try it tomorrow it is cold out but it has lost significant amount of power and I cant see how weather would have that much of an effect.
Sounds like it could have a tired clutch. Ride along in 3rd gear apply the throttle and drag the front brake , if the RPM's increase but the speed doesn't you need a new clutch. Use the front brake to load the engine, if the bike slows without the R's dropping it's the clutch.