250x won't snap back to idle
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    speeedracer62
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    250x won't snap back to idle

    by speeedracer62 » Mon Mar 22, 2010 8:49 am

    I finally scored the bike I've wanted for a long time, a 250X. I got a great deal on a stock 2006 model (except for a power bomb header) with no hours on it. That is where the problem is I think. Its been sitting still too long with junk gas.

    It was hard to start (I know they are normally) but once it starts and warms up it wouldn't idle. And when it was running the engine RPM wouldn't lower naturally, it would just run high for a bit then stumble to the point of dying.

    I felt that the carb was gunked up so I removed the bowl and cleaned it and found a clogged slow jet. Now it will idle when I first start it but it still won't immediately return to idle after letting off the throttle.

    I know its getting too much fuel but I'm not sure what to check.

    Any ideas you could give me would be appreciated!
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    bosshaug1
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    Re: 250x won't snap back to idle

    by bosshaug1 » Mon Mar 22, 2010 8:57 am

    speeedracer62 wrote:I got a great deal on a stock 2006 model (except for a power bomb header) with no hours on it. That is where the problem is I think...

    ...Now it will idle when I first start it but it still won't immediately return to idle after letting off the throttle.

    I know its getting too much fuel


    Actually if it is stock it is getting too little fuel, as hanging idle is a symptom of that. Initially you could try opening up the fuel screw, but if you want a great running/riding/easy to start bike, then get the JD jetting kit and do all the mods.

    Search here for many discussions on the mods, and ask questions -we will be glad to help.
    Image
    2006 CRF250X -JD kit, R can/PMB endcap, CCC mods, 05Rcam, flatland rad guards/skidplate, street legal
    2003 CR85R -stock, son#1
    2005 CRF50F -stock, son#2
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    AgentSmith
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    Re: 250x won't snap back to idle

    by AgentSmith » Mon Mar 22, 2010 9:09 am

    speeedracer62 wrote:
    It was hard to start (I know they are normally)



    Who told you this?? :shock:

    CRF 250X's start easily...no problems with that.

    Follow Boss's advice on the JD kit. Replace the slow (pilot) jet with a NEW 42 and all will be well.
    "Make a man a fire and he'll be warm for a day.
    Light a man on fire and he'll be warm for the rest of his life."
    Image
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    speeedracer62
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    by speeedracer62 » Thu Mar 25, 2010 3:40 pm

    Thanks guys! I've ordered the kit and hope to install it this weekend. I'll post my results afterwards.

    Great site, Thanks again!
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    walkmnn
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    by walkmnn » Thu Mar 25, 2010 4:53 pm

    HARD TO START? Maybe it sounds like a valve adjustment as well. 2006 model, might be time? What's the history?
    Follow the How-to:
    http://crfsonly.com/howto/crf250x/crf-v ... stment.php

    Walkmnn
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    speeedracer62
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    by speeedracer62 » Fri Mar 26, 2010 5:45 am

    Walkmnn, even though its an '06 its nearly brand new. It has almost no scratches at all. Even the side case next to your right foot shows no wear. The adult guy bought this while he still had a hopped up CRF230 and a nice Rancher 4X4. Guess he thought it was too fast and rode the other 2 instead.


    I received my JD kit yesterday and plan on installing it today. I figured since I'm in that area I'd go ahead and check the valves. Thanks for the link!

    Speed
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    walkmnn
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    by walkmnn » Fri Mar 26, 2010 9:00 am

    Speedracer62,
    While your in the carb take notes and keep notes on stuff like size of jets. It will help in future questions. I know you just purchased the JD kit and that will help. When you check the valves and if they are in spec great, your done, don't touch them. If they are out of spec take notes on the size shim you pulled out compared to the size you use to get it back into spec. Now try and keep track of about how many hours you ride on the new shim size. This will let you know how your bike is running when you have to reshim.

    I talk to much.

    Walkmnn
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    speeedracer62
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    by speeedracer62 » Sat Mar 27, 2010 2:21 pm

    Gents,

    I installed the JD kit today by installing the new pilot 42 and the 165 main jet because this '06 250X has the air box mods (no top and no screen) and it has a FMF power bomb header with the stock muffler. I installed the new needle with the clip in the 5th groove too.

    I was going to do the AP mod, but my accelerator pump nub was already small (2mm). I did put the small O-ring on the pump screw.

    Next I lightly seated the fuel screw and started at 1 3/4 turns out. I cleaned the TwinAir filter and loaded her with fresh 93 octane fuel and fired her up.

    I hate to say it but it STILL hangs up with a high idle. When I rev it, it does drop a few RPM but not back to a normal idle. Sometimes it will just still there at a high RPM then settle down to a normal idle, other times it just idles abnormally high and won't return to a normal idle.

    I tried turning in the fuel screw 1/4 turn at a time down to 3/4 out but it didn't make any difference.

    Could trash inside the carb cause such an issue? Initially the pilot was clogged when I got the bike and the bowl was pretty crappy. I cleaned everything I could reach and sprayed carb cleaner up the passage ways.

    Could this be a timing issue? I just don't know what to look at next.

    Your suggestions would be greatly appreciated!

    Speed
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    speeedracer62
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    by speeedracer62 » Sat Mar 27, 2010 4:10 pm

    Just a few more details I wanted to share with you about my troubleshooting....

    1) I tried disconnecting the TPS, this made no difference.

    2) I shot carb cleaner all around the carb looking for air leaks, none were found.

    3) After reading more posts I tried setting the idle screw to a good RPM by ear. Then I turned the fuel screw out, first to 2 turns, then 2.5 then out to 3. Didn't seem to make a difference.

    I had read somewhere that said if your out past two turns you should increase the pilot jet size. The one I started with was a 42, as was the new one with the JD kit. Maybe I should increase this to 45? 48?

    What do you think?
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    walkmnn
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    by walkmnn » Sun Mar 28, 2010 3:27 pm

    I have an 04 250x with the R cam and I run 165/45 and 70 leak jet. 2 to 2 1/4 turns out. My only issue is from idle to quick with open it bogs a little and then great. From mid rpms to a quick wide open is perfect and snappy. I've been trying to tune it for a couple of days trying different things and can't quite get it 100%. Any suggestions?

    Walkmnn
  • Halen
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    by Halen » Sun Mar 28, 2010 6:35 pm

    Have you adjusted your idle screw at all..?
    I had the same problem where the idle screw actually broke inside the sleeve.
    Start your bike...
    rev the machine and turn the idle...
    release the throttle...
    repeat...
    repeat...
    repeat...
    ALWAYS have the throttle turned when you are making adjustments. If not, there is pressure placed on the throttle mechanism and it may break...
    just my $0.02

    later... Van
    09 CRF 250R
    RMR lowered suspension
    Heavily armoured for the bush
    50 tooth rear
    soft gel seat
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    speeedracer62
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    by speeedracer62 » Sun Mar 28, 2010 7:10 pm

    Halen,
    Yes I have tried adjusting the idle screw. It appears to be working fine. Once the RPM's die down I can change the idle up or down with the screw. My problem is that the bike has a real hard time returning to the idle RPM after I'm on the gas. It doesn't matter if I feed it slowly or blip the throttle, the RPM's will stay high for some time, 5-10 seconds, then return to idle or sometimes it rev's indefinitely.
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    speeedracer62
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    by speeedracer62 » Tue Mar 30, 2010 7:06 pm

    Just wanted to update the status of my bike..it runs SOOOO NICE now. I did all the mods above and it was still running crappy with a high idle. So I replaced the 42 pilot jet with a 45. This seemed to help but was still not perfect, ie a blip of throttle would result in a slow return to idle. Add in the factor that I couldn't really get to the fuel screw easily to adjust it while it was running was really frustrating.

    Next I went and bought the R&D Flex-Jet fuel screw and installed it along with a new 48 pilot jet. This combination really WOKE it up. The bike starts easily, idles very nicely and the throttle response is crisp and QUICK. It revs up and down the way a finely tuned bike should. And there is NO BOG off idle whatsoever!

    Thanks to ~ and Bosshaug for their excellent advice!
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    bosshaug1
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    by bosshaug1 » Tue Mar 30, 2010 8:01 pm

    Glad to hear the bike is running so well and that we were able to help!
    Image
    2006 CRF250X -JD kit, R can/PMB endcap, CCC mods, 05Rcam, flatland rad guards/skidplate, street legal
    2003 CR85R -stock, son#1
    2005 CRF50F -stock, son#2
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    walkmnn
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    by walkmnn » Wed Mar 31, 2010 8:50 am

    Speedracer62,
    Congrats on the solution. Now get out and enjoy. I might try to go to a 48 pilot. My bike starts fine, idles fine at around 1800rpm's. It doesn't have that snappy response from idle to wide open, there is a little bog and hesitation the kicks in. Here are my spex below. My bike has the 05 R cam as well. Any help to get rid of the bog would be much appreciated.

    Thank you

    Walkmnn

    Year: 2004X
    Elevation: 0-3000
    Temperature Range: 60-100f
    Smog (AIS): NO JB WELD
    Airbox Modified Top: YES
    Airbox Modified Sides: YES
    Backfire Screen: REMOVED
    Air Filter: MOOSE RACING
    Pilot Jet: 45
    Main Jet: 165
    Needle: NCYS
    Needle Clip Position: 4th
    Fuel Screw Type: CRF's ONLY
    Fuel Screw Setting: 2 1/4 out
    AP Modified: NO
    Leak Jet: 70
    AP Cover: STOCK
    Exhaust Type: STOCK
    Exhaust Modified:BAFFLE REMOVED
    Pink Wire Modified: YES

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