2007 KLX250s, all stock except for header, pipe, jets and smog delete. Under 2000 miles.

I've been riding a short distance to and from work most of the summer (barely over a mile each way) . It's been running great, riding great, the only issue I've had was that my key was getting a little sticky, it was hard to put in all the way, it would get caught just before it pushed in the last bit and then it was slightly hard to turn. Last week i put a small shot of WD in the ignition and ran my key in and out to loosen it up. That worked after a few cycles, so did the bike. A day or two later on the way to work it cut out (earlier than I would have normally hit reserve) I switched to reserve, no rapid joy, just slowly decelerating until the motor suddenly caught and I finished my short ride. It felt just like hitting reserve at speed where it can cuts out of power very suddenly, but it died again pulling in the parking lot while on reserve, but I had enough momentum to park it and work. Leaving, I tipped the bike way over left in case I was low on gas for some inexplicable reason. I was thinking maybe I'd been on reserve not realizing it (like the taller pipe inside broke, or the petcock was letting it all through and run out somehow. It was still a little hard starting and the choke point felt weird (half instead of held out to just before the click) but it started, so I left for home, on the way home (under 2 miles) it cut out 2 or 3 more times where it seemed like I suddenly had no power and I essentially coasted a while until the motor suddenly caught again. The next day I checked for water in the fuel, no signs of that, but I added more gas and fired it up, rode around the property, after it got warm it bucked once just slightly like it had misfired or coughed, then shortly after that it quit completely again, and was hard starting. The battery got a little weak, so I threw it on a charger, and did the same thing again the next day. Today I checked the kill switch, completely disassembled it, no signs of anything wrong but I lightly sanded the contacts just in case. I checked the spark plug, no signs of anything wrong there. I checked the petcock, fuel flows freely out of both tubes. I pulled the tank, and found a rotted out vacuum plug on the top of the carb from my delete. I replaced it, and reran the bike, it fired right up, I turned up the idle a bit (it tends to idle a little slow and stall out until it's warmed up) and I let it run, after a few minutes it quit again suddenly and didn't feel like it wanted to restart easily. I tried to check the spark at this point fairly quickly (2-3 minutes to get the screw driver, pull the wire, get situated and spin the motor over). looked like it had spark at that point, can't be 100% sure it had it when it quit. I pulled the bottom of the carb, no signs there of moisture inside or any physical issues with float or needle valve that I can see and the carb did seem to have fuel in it when it quit. Now I'm wondering if anyone has any further ideas. The quit is sudden and I can be idling or riding at 40 mph, it seems to happen after a few minutes of running so I'd say it's warmed up at that point. I'm wondering if maybe a bit of the dry rotted vacuum cap could have gotten sucked in someplace, or if maybe the ignition could have a brief intermittent short from the WD that I'm not detecting, or [insert your better idea here] Thoughts welcome. Definitely want to continue riding to and from work as long as the weather holds. I'd love to have a wiring diagram of the ignition so that I can hotwire the plug underneath just as a test to confirm the ignition is not related. Thanks in advance.

 

I am due for an oil change, but it did not appear low on oil in the sight glass, but I did consider maybe it has a low oil sensor that could flake out?

 

The wiring diagram won't get you all the way to hotwiring this bike.

Have you disabled either your kickstand or clutch safety switches? If not (or so), look at those two as possibilities along with the obvious one of something in the carb due to the rotted plug. I doubt the ignition is the problem but who knows. Did you try wiggling the key when it cut out?

 

I haven't disabled any safety switches, hadn't thought of checking them, but I tried starting it and it had spark, the safety switches would have to cut the spark on it, so I can't imagine that's it. I had the carb off the bike and the vacuum hole led straight to the intake so even if it sucked something up, it chewed it up and spit it out the back end of the engine, not much chance anything from that went into the actual carb orifices. In other news I tried to put it back together and start it and now it won't start at all but has spark, and cranks fine, and fuel flows out of the bottom of the carb if I use the drain plug. I blew out the orifices with an air gun a bit and double checked the float was functioning and that seemed in order, only thing I can think is if either the gas is flat out bad but not visibly with water (which is hard to imagine as the bike was running fine one day, bad the next?) or there is something amiss in the carb beyond a quick air dry/blow out. I did realign the TPS sensor when I put it back together as well. Tomorrow I'll dig deeper in the carb... le'sigh.

 

Did you just clean the carb?
If so, there is your problem.
I don't think you have a switch problem. To check the spark, you need a spare plug, not a wiring diagram.

 

I don't think the TPS sensor does a thing for your '07. I've run with and without it connected. The TM36-68 carb has no provision for it. Disabling the kick stand switch is as easy as following the two wires up from the kickstand to where they connect under the seat, disconnecting them from the kick stand, then connecting the wires together. Unlikely problem, but easy to diagnose.

 

Is it possible this could be a ground issue somewhere?


One thought, when it stumbles and stalls, instantly turn off the gas petcock. then open the carb drain and see if there is adequate gas in the float bowl. That could isolate and eliminate lack of fuel.

When it's electrics I'm lost.

 

Bypass the kick stand safety switch and then ride it.
Mine would cut out over bumpy roads, bypassed it and no more problems.
K.I.S.S. usually fixes most problems.

 

I checked spark by pulling the plug wire, sticking a screw driver in the plug wire and holding it near the frame while cranking. It had plenty of spark, unless the plug itself has an invisible defect but I'll check the spark with the actual plug tomorrow. I blew the carb out a little with compressed air, but with no carb cleaner yet because I didn't have time to take it completely apart and move all the seals to a safe alternate location to keep them from swelling up. All I did was pull the float bowl off, blow through the jets with compressed air, pull the choke out and blow that area out, and blow into the orifices on the front end of the carb. Tomorrow I'll run some thin wire through things over some clean parts pans, pull the jets, use some carb cleaner and and see where that get's me. Who knows, maybe my compressed air moved something partially blocking a passage into totally blocking it? I did note that the slide seems to be moving smoothly as well. If it's a short, I don't get why I'd have good spark but it won't start. I gotta find the computer that I have the manual for this thing and comb over the carb I guess. Which means I'm probably not riding to work till next week sometime. More ideas welcome.

 

Did you rejet after moving to New Jersey? Jackson Hole is quite a bit higher.