Pardon the double post, but I just found the KLX 250S forum...

Today my 2007 KLX 250S with 7500 miles died abruptly (no misfiring, coughing, etc) about 5 miles after refueling. I limped home at 15 mph in 4th, installed new NGK plug, checked the air filter (100 miles old) but NFG. When I open the throttle, it goes to about 2500 rpm, then dies. If I release the throttle, it idles normally. If it stalls, it starts right up. The KLX is new to me about 300 miles ago. Is this a known "feature" of these bikes? Any suggestions for troubleshooting or fixes will be much appreciated.

 

Is the choke on? Happened to me. Make sure it's off.

 

Yup, it's off. Now that you mention it, the bike runs just like it's cold with the choke off. I tried pulling the choke on and it died immediately from idle...

 

Might also be partially clogged jet . I'm out of ideas. hope things work out for you. Post if you found out what's wrong and the fix. Thanks.

 

Problem arose after refueling.
Did anything else happen?
Could a vent line have gotten pinched somhow? I have a '09 so I don't know how the '07 vents the fuel tank. Did something happen with the filler cap?

Just typing out loud here folks.

 

I suspect trash in the main jet....it may be completely clogged off.

 

Ol'klx-er is on the track I would be on. If it happened just after refuel then I would say either you picked up crap from the bottom your tank or you picked up crap from the bottom of their tank.

I put gas in an old toyota once and it ran like poo until I ran the gas out.

I would try an drain the tank. Cheap to try.

 

Probably water in the gas, drain the carb bowl or put a bunch of gas additive in the tank to absorb the water. (do this after draining the tank & filling up with fresh gas). The gas floats to the top of the bowl and runs ok until it really starts sucking it up, then it gets a slug of water.

 

The timing of it would tell me to look at the last thing that happened... you re-fueled it.

I'd bet BAD GAS, and that's certainly where I'd start looking first. Could be water, or crud in the gas. Accordingly, it may require removal of carb and checking for water in the float, or junk in the jets.

 

Yesterday I drained the tank thru the float bowl drain and refilled the tank with fresh gas + 2 oz. of Startron enzyme fuel additive - great stuff. The problem remained. Today I managed to remove the 3" diameter tube between the airbox and carb. I then raised the slide and blew compressed air down thru the mainjet using a short piece of vacuum hose on my airgun. She fired right up and went to 7000 rpm with a twist of the grip. Then I put 25 miles on and she ran great. When I go back up north in a few weeks, I'll take the carb with me and clean out that float bowl when I do the rejet and other popular mods. I won't be riding far from home until that gets done. Thanks to you KLX 250 guys for the great suggestions. I love this forum.