Hey everyone. My 650 has been having a slight problem. From about 3/4 throttle on, usually when flying down the road(not so noticible on the trails) it seems to hesitate momentarily, after riding @ the same throttle position for a short while. It doesn,t seem to make any kind of coughing noise or backfire, but I can fell it kinda bog for a second, then take off again. If I give it more throttle, it seems to clear up, then will do it again once @ the new throttle pos. for a short time. Other than this, it seems to run great, aside from a lack of top speed(I think), could be the tires?? Any ideas would be appreciated - jetting? I did clean and re-oil filter after this started, but no change.

 

went for a good ride yesterday, lots of mud and water, yee-hah!! Anyway, bogging problem seems to maybe be a bit worse, but it was reminding me of my old atc, the fuel tank vent would close off and it would make kind of a coughing noise from the airbox. 650 is making the same noise. I checked the vent lines and they all seemed to be fine, no kinks till where they tie into the frame. Does anyone know if the frame is vented somewhere else? Seems like it must be, but where to. If anyone knows a cure, please let me know.

 

Try opening the gas cap after it is doing it, and see if it suck in an abnormal amount of air. If so, try leaving it cracked open little during a run and see if it changes things.

 

sounds like you could be a tad rich. Is it worse when the bike has warmed up? Have you looked at your spark plugs? I'd check your air screws and see where they are. Most of us have them between 2.5 and 3 turns out. I found mine was very lean from the factory, and would cough/sputter when cold and up steep hills. Once I corrected this it started much more quickly and the sputter was mostly eliminated.

 

Is the air filter clean and re-oiled properly?[img]i/expressions/face-icon-small-wink.gif[/img]

 

This is the early indication that I had when my sliders in my carb went. You should see this on rougher/slower trails if it was your carbs sliders. I would say you're running rich.