Idle jet
  • Sam400
    Posts: 14
    Joined: Sun Jul 19, 2020 2:30 am

    Idle jet

    by Sam400 » Wed Aug 19, 2020 12:33 am

    What is your elevation ?? _________0ft______

    What type of riding are you doing ?? ___________mx/enduro________

    What is your Fuel Screw set at ?? ______1 7/8 out______

    What jets are in it (Pilot/Main) ?? ___42___/____178__

    What is the Needle Clip Position ?? (IE: 3rd from top , etc.) ________3rd____

    Was the bike running fine then just started doing this ?? , or was it like this when you bought it , or after sitting for a extended period ?? __________________Bought as non runner ____________________________________________________________________________

    Have you actually pulled the carb and cleaned it (removing all the rubber parts like Fuel Screw O-Ring , Slide , Floating Slide Plate O-Ring , gaskets , jets , and flushed everything with carb cleaner and blown out with air) ??? ______________________Yes ultra sonic clean and full rebuild_________

    Do you have a Manual ??? (Yes/No) ___Yes__/_____

    Have you lifted the subframe and airbox , and looked down the throat of the carb and twisted the throttle to see if the accelerator pump is squirting ?? , and if it just barely misses the slide and does not hit it ??? ___________________________yea AP rebuilt and set up _______________

    When/if you took the carb apart , did you note which way the floating plate is on the slide ?? , was the hole at the bottom ?? , or the Top ?? , it needs to be at the bottom .. ______________Yes fitted correctly ______

    Did you drain and flush the tank and put FRESH Premium in ?? _________________Yes fresh E0 carb drained after use _

    Was the bike sitting for a long time (over 3 months with gas in it , if so see above last 2 questions) ?? _______________Yes_____

    If the bike was recently purchased , was the prior owner up front and explained the issues with the bike ?? , and if it was recently purchased how long have you had the bike , and were the issues present then ? Non runner


    Hi guys, I have crf250r 2008, it likes the hot start to start from cold, I assume it’s running rich.

    I can wind the fuel screw all the way in and bike doesn’t die. Currently have a 42 pilot in there.
    Not sure whether to drop too a 40 or look at other issues?
    Have replaced most of the components in carb but thought the main jet holder could be worn oval?
    Can’t see any wear with naked eye?

    What’s your thoughts

    Thanks

    Sam
  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: Idle jet

    by Back2-2 » Wed Aug 19, 2020 9:35 am

    You did not say how the bike runs once fired and at full operating temps, so from what you did described - I would go one size down on the PJ. Very doubtful that the wear if any, on the jet holder is your issue. Pin gauge set is perfect for checking dimensions.
    Verify the A/F screws spring, washer, o-rings condition and orientation.
    Check for air leaks - everywhere.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • Leardriver
    Posts: 462
    Joined: Wed May 05, 2010 10:33 am

    Re: Idle jet

    by Leardriver » Thu Aug 20, 2020 1:43 pm

    The jetting settings didn't just go bad if it ran fine before it sat. Always start with a new pilot jet, not a cleaned one. it seems to solve 80% if idle and starting problems.

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