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Thread: Help!! 2017.5 250 sxf idles but wonít rev

  1. #1

    Default Help!! 2017.5 250 sxf idles but wonít rev

    I just picked up a 2017.5 250sxf factory edition with 20 hours.

    BACKGROUND the previous owner was the second owner who rode the bike for a couple hours and the battery died. he replaced the battery and rode it another couple hours and the battery died. After testing the stator decided it wasnít working and replaced it. After that the bike sat for almost a year. He went to start it and said it was running rough. Which leads us to current.

    I have a 2019 KTM 350 sxf also. I have swapped the entire throttle body (including sensors), fuel tank with fuel pump, ignition coil, relay, and condenser. No FI light flashing. I have unplugged each sensor as itís running and the FI light will start flashing. I also pulled the valve cover to inspect the cams and verify the oil jets were spraying oil as I know these bikes have had oil pump issues. Tested ohms of the stator and pick up coil also visually inspected the coils. All appear to be good.

    ISSUE the bike will start right up and idle without issue. It is responsive to short throttle blips and idles back down immediately. Once it reaches approximately 1/4 to 1/3 throttle the bike acts likes itís in gear and the rear brake was stood on. Engine sound like it starts to get a load on it and it dies immediately. The bike will Fire right back up and idle as long as you want. 🤯 Iím losing my mind!

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  3. #2
    KTMTalk Member
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    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    Verify the cam timing. Could have jumped.
    '18 350 SXF
    '09 150 200SX
    '09 518 EXC SM Tagged
    '08 505 XCF Tagged

    '08 450 SXF Rekluse
    '02 Honda 919
    '91 Honda VFR 750
    '92 Yamaha TDM 850
    '88 Honda NX 650
    '88 Honda NT 650 Hawk Blue

    '12 BMW R1200R Classic,

  4. #3

    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    I will double check it. I would think it would be hard starting or run rough at idle as well if that was the case

  5. #4

    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    Cam timing and valve clearance verified. Also have now swapped the stator and pick coil as well as the ECU. Literally every component other than the wire harness and gear position sensor has been swapped out with my 2019 and it is still doing the same thing! This thing is going to drive me bat-****-crazy!!

  6. #5
    KTMTalk Member
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    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    Have you installed a new spark plug?

  7. #6

    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    Quote Originally Posted by beech View Post
    Have you installed a new spark plug?

    .
    2018 KTM 150 SX
    2018 Husy 85 bigwheel
    08' 250 XCF-W
    14' 350 EXC-F
    09' BMW 1200GS Adventure- For Sale
    1970 PW50 Indian

    Special thanks to RSMX, GoPro, SCOTT, SIDI, Acerbis, FMF, Leatt, Asterisk,

  8. #7

    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    Yep replaced the spark plug with a new NGK

  9. #8
    KTMTalk Member
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    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    First, make sure that there are no obstructions in the intake or exhaust. Second, place a volt meter on the battery and start the bike and measure the voltage. Then blip the throttle and/or raise the RPM and see if there is a change in the voltage.

  10. #9
    KTMTalk Member
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    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    My 17 350 did that turned out to be the fuel pump only putting out 32-38 psi. Replaced the fuel pump with after market 50 hours later all good.
    Woods Racer
    05 300EXC SOLD
    12 350 XCF-W
    17 350 EXCF

  11. #10

    Default Re: Help!! 2017.5 250 sxf idles but wonít rev

    No blockage in intake or exhaust, checked charge at battery (does increase with throttle blip), also swapped tank with fuel pump off a 2019 350. Iím down to mechanical, wire harness, and havenít swapped what I believe to be the gear position sensor. Cam timing and valve clearance spot on. The head pounding continues. Performing a leak down test tomorrow

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