i have just bought a 2011 kx250f and it seems to have a problem with idling. after warning it up, it idles for 1 min and then seems to kill itself. i,ve tryed adjusting the idle screw (also the choke) but this does nothing for the problem only makes the bike run too high when riding.
any suggestions welcome.
today was first day taking the bike out for a spin.

 

Welcome to KF and congrats on the new ride.

Is the vent clear for the tank?

Hit up the KLX section here, those guys know their KLX's.

 

Try get carb spray cleaner . Start your bike then spray around the card , hoses etc. if idle goes up then you have vacuum leak. Fixed my klx 250s hanging idle that way

 

Well there are many things effect to this problem. Like the bad spark or spark plug. or may be there is some problem in fuel circulation or air filter.

 

Thank You for your help and suggestions so far. We tried alot. Actually brought in another bike and switched over tanks, Injectiors, TPS and ECU and none of it changed the bike. I have a feeling it is with the hot cams, valves or the head. Does anyone know if the stage 2 hot cams need a different timing setting, a little more advance or retard on the intakes or exhaust?

 

there was a small part of the right exhaust valve spring broken and therefore not closing fully.. new valves and springs fitted now and my bike runs like a mouses' heart.

 

Dang, that one wasn't easy to diagnose in a forum...

Thanks for letting us know.

 

dang, would you by chance of pics of that slightly broken exhaust spring? How did you find that? During a leak down test? Just curious, congrats on the fix.

 

i was checking valve clearance and whatever i did i could not get the clearance right. i decided it was time for new valves and reseating. when i had the head removed, i turned it over to inspect the valve heads and seats and low and behold i heard something move. i flipped over again and spotted a piece of the valve spring beside the top of the valve. removed it with a magnet and sent the head to my dealer to have valves and springs replaced under shop warranty.

 

merlin, are you starting your bike in cold weather? and what size are your jets? if you plan on riding in colder weathers, might suggest getting bigger jets.....i had the same proble