Author Topic: 2011 KX250f Mystery problem  (Read 312 times)

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Offline cdziekan

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2011 KX250f Mystery problem
« on: March 03, 2021, 04:39:18 PM »
Hi I recently bought a really really clean 2011 kx250f that was completely rebuilt by a mechanic. I took her to the track and it ran absolutely perfect and sounds awesome, but we had the common oil leak problem from the sparkplug weep hole on the right side of the cylinder so we took off the valve cover and put sealant on the top o ring right below the valve cover (the only thing we did) and we think it fixed the oil leak problem without having to take off the cam caps to get to the second o ring, but after reassembling and putting the gas tank back on we started it up and it ran horribly almost sounds like a misfire and is blowing white smoke out the exhaust, which is neither coolant or oil being burned for sure, so it has to be fuel?  Also my timing is perfect we never did anything more than taking the valve cover off and now its running so off and wont idle, you have to play with the throttle to keep it running. I'm so stumped any ideas? Fuel injector problem? Spark problem?(I never did end up changing the sparkplug, and oil did leak into the sparkplug chamber cause the leak) Also here is a video of how its running with sound. https://youtu.be/T0vNBR_dXKg


 

 Any help would be greatly appreciated before I take this thing to a shop....

TLDR: Bike ran amazing, Wanted to fix easy oil leak, took off fuel tank completely, took off valve cover and nothing else, added sealant to o ring right below valve cover to prevent oil leak from weep hole, reassembled fully, doesn't run right, misfire? didn't change/mess with anything to cause a problem like this but here we are

Offline motorman455

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Re: 2011 KX250f Mystery problem
« Reply #1 on: March 04, 2021, 03:54:30 AM »
Perhaps something to do with the fuel pump or connection?

Offline cdziekan

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Re: 2011 KX250f Mystery problem
« Reply #2 on: March 04, 2021, 01:28:40 PM »
Possibly, thats what were thinking, everything seems to be plugged in and connected properly, i just dont know...

Offline KXDINO

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Re: 2011 KX250f Mystery problem
« Reply #3 on: March 06, 2021, 09:37:03 PM »
Is there any water in the fuel , clean tank etc .

Offline cdziekan

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Re: 2011 KX250f Mystery problem
« Reply #4 on: March 10, 2021, 11:34:31 AM »
Okay so I believe I found the problem but the bike is still not acting right, The two throttle cables leading down to the fuel injector were very loose (i noticed this days ago but i thought it was a adjustment and not to mess with it) When I tightened it up the bike runs perfectly but for about 30 seconds then goes back to running like crap..... but definitely major improvement and I don't know where to go from here... new throttle cables idk?