power valve sticking? any help?

[nambo-trev]

hi guys, im just getting my bike ready for our first winter ride after sitting for about 3 months, the bike fired up and after a short warm up i took it through the gears and all is good power wise and shifting but as soon as i stop to turn around the bike goes into over rev like the power valve is wide open. when i start riding again it returns to acting normal. the throttle tube is good and no cable sticking it just runs away every time i stop. any ideas or suggestions? this is also my brand new engine with maybe 4 rides on it.

 

[GMP]

Nothing to do with the PV. If your sure the slide is returning fully then its lean. If it ran crisp when warm then perhaps jetting or a clogged pilot, but I'd check for an air leak.

 

[nambo-trev]

can this occur from sitting to long? a clogged pilot i mean? i havnt changed a thing since my last ride. ill check the carb tomorrow

 

[GMP]

Yes it can from fuel degrading. Please tell us you used fresh premix.

 

[nambo-trev]

negative, i didnt. i though its only 3 months with a high octane fuel so i didnt think there could be significant degredation, but after the bike acted up the first thing i thought was "i should have drained the fuel".

 

[widebear]

High humidity cold temperatures and a sticky oily deposit left on the slide from the air filter oil can make the throttle return lazy. It will have a milky appearence, sometimes the water comes from a wet air filter as a result of starting the bike after washing. You can also loose the jambnut on the brass tube that locates the throttle cable on top of the carb cap. You dont need it and it will free up some extra cable for more slack.

 

[GMP]

Three months? It was trash a long time ago. In three weeks my gas goes in the weedwacker can. Start over, you need to drain everything and clean the carb, paying attention to the pilot and slide function.

Widebear brings up a good point about the throttle cable. Its right on the edge of being too short, and better off being replaced with the +1.5" Motion pro cable. Ever hit a tree on a 300 with a stuck throttle from a jammed cable? Been there, its painful and expensive.