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Kx250f stalling off clutch

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Hey guys, I just picked up a 2014 kx250f with 3 hours on an entire rebuild for 1700 (not running). When I got home, I was able to get the bike running, however when I come off the clutch from first, the bike stalls no matter the RPM. Is this a clutch issue? Or perhaps electrical? When I tore into the top end I did notice my exhaust valves were off spec so could this be the culprit? This is my first FI bike, so any advice helps. Thanks in advance

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What you say is:

- it runs in neutral with clutch pulled

- it runs in neutral with clutch released

- it runs with clutch pulled and geared into first

- it stalls when in first gear and clutch is released.

 

Driveline jammed? Or just Bogs and dies?May be an error in re-assembly of the transmission or clutch mechanism. Dies the tire turn freely when up on a stand?

Please be explain further.

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What you say is:

- it runs in neutral with clutch pulled

- it runs in neutral with clutch released

- it runs with clutch pulled and geared into first

- it stalls when in first gear and clutch is released.

 

Driveline jammed? Or just Bogs and dies?May be an error in re-assembly of the transmission or clutch mechanism. Dies the tire turn freely when up on a stand?

Please be explain further.

 

Thanks for the response. As of right now the bike is apart waiting to get new valve shims hopefully tomorrow, I will then be able to assemble it and check if the tire spins freely. I would hope it's not an error in the transmission considering the rebuild didn't consist of anything other than the crank and top end, but who knows. The most I can really tell you about the bike (bought it yesterday) is that it's extremely hard to start (which hopefully is just the out of spec valves) and that it dies only when you come off of the clutch. Although if you're asking if the wheel spins freely in neutral with the bike off, then yes it does.

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I guess, I still do not understand what you mean when you say "come off the clutch".

To replace the crank, the cases have to be split, which opens the transmission as well.  There in is why I am asking for clarification to determine if it is a locked up transmission issue (something out of place inside) or if it is a tuning/timing/electrical issue.

 

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I guess, I still do not understand what you mean when you say "come off the clutch".
To replace the crank, the cases have to be split, which opens the transmission as well.  There in is why I am asking for clarification to determine if it is a locked up transmission issue (something out of place inside) or if it is a tuning/timing/electrical issue.
 


I must of had a mental block at the time lol i don't know why I forgot that the cases had to be split, but what leads me to believe that it's not a transmission error is that the previous owner had already put a couple hours on the bike before it stopped running, so I'm hoping that any issues would have made themselves clear during those first few hours but who knows. What I mean by come off the clutch is that when I shift the bike into first and gradually let the lever release as I give it gas, the bike stalls. And this happens no matter how high the RPM is when I come off the clutch. So basically the bike will run when it's in neutral or has the clutch pulled in when in gear, but the second you go to set the bike in motion it will cut out regardless of how hard you come off the clutch. I want to lean towards an electrical issue because it seems as if it's at the flick of a switch that the engine dies under the same circumstance each time, but the clutch is also a likely culprit however upon inspection, the plates and basket looked mint.

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Does bike shift through each gear when on stand like it should? Or did you try releasing clutch with tire off ground to verify it wasn't just stuck clutch plates.

Valves being out out of spec wouldn't stall the bike like you are saying. It may not run great or be hard to kick start but it shouldn't stall....make sure nuetral safety switch is functioning. 

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Does bike shift through each gear when on stand like it should? Or did you try releasing clutch with tire off ground to verify it wasn't just stuck clutch plates.
Valves being out out of spec wouldn't stall the bike like you are saying. It may not run great or be hard to kick start but it shouldn't stall....make sure nuetral safety switch is functioning. 


Thanks for the reply. The bikes transmission seems to function fine when the bike is off. I just put the bike back together after reshimming the valves and I noticed the idle is a bit erratic. This leads me to believe my fuel pump may be failing, also because header had a bit of smoke coming off it so I'm thinking it's running lean. Any input?

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