KXF 250 2011 sometimes stutters and not acceleration

Hello . Averagely twice a week i have strange problems with my kxf 250 2011. During the run suddenly bike starts to work strange i mean : i pull off gas maximally and bike dont accelerate even a bit, and starts to stutter... when i turn bike off and make restart immediately, everything its OK ! Like i said it happens rarely but one time it happened on the jump and i almost done front flip :/ its dangerous to ride like that and i have to fix that problem. My friend told me that maybe air sensor is dammaged?? I checked all connectors and it all seems ok... 
Looking for help guys ... 

Hey Lapkos, I had a similar issue on my KX250 while I was riding in a race, then when I got back home I plugged my computer on the bike and got a reading from all sensors and the throtle one was not giving any feedback, I unplugged its plug and found dusty inside, cleaned it and reconnected, then got readings from 0% to 78% on the computer and since then the bike has been working fine,


So check the throtle sensor's plug and ensure it's clean and secured.



I checked and cleaned throttle sensor connector and after few rides problem was back again. I tested sensor like manual said and resistance , output, input V are good. Its possible that throttle sensor is dammaged ?
Important thing to accentuate i think...-> after restart everything is ok ... problem back again sometimes at next ride or  sometimes for 2-3 weeks... 


Sounds like you may have a bad coil . ( shorting ) or the cdi is failing. do test on them and if ok , then check the stator windings .

reason I think it is ignition is when you shut it down and let it cool a bit it fires right up. Windings  and capacitors get hot and fail. then when cooled of they operate normally till hot again.

I forget... It hapens even on cold engine... After first start in a day immediately problem may occured...but on cold engine it happens less often

Edited by Lapkos

Like I said it sounds electrical. If restarting changes the way it runs you may have a bad ecm ( engine control module ) You need to borrow a tuning tool and look at whats going on there. You should be able to see all the sensors. check their performance, reproduce the stutter and look at all the live data.


I would check all of the ground wires for this bike also. I think most are under the gas tank / coil area.

Let us know.


If you dont have access to a tuning tool you can start with wiring in a 12 volt light source.


There is a 6 pin connector behind your number plate. The red/white and blue/white are the wires to hook up a 12 volt light. Tap into those wires and start the bike. If the dfi system doesnt see any current issues the light will go off after 2 secs of the bike running. If you have a problem the light will stay on. From that point you would have to ground the yellow wire from the same 6 pin harness and it will give you codes using slow and fast flashes. 

Edited by Taco13

I did not know this system had self diagnostics, good info. Saves me a lot of time. Thanks.


I have to add one more thing. If the light does stay on you should test for codes with the bike off. You can power the bike with a 12 volt power supply. You unplug  the green plug that is located on the left side of the bike. You will hear the fuel pump turn on for about 30 secs then it will turn off. You can see this plug in Dragons TPS video. He explains how to power the bike and the location. 

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