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Thread: Carb needle question

  1. #1
    unclejemima is offline At The Back Of The Pack Arm chair racerFirst time rider
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    Oct 2009
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    Canada
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    Carb needle question

    I rebuilt the carb in my 86 Honda ATC 125M with a carb kit from Keyster. It worked like crap. The main jet size the kit came with was different than stock, and the needle retaining clip was totally the wrong size, almost like it was the wrong kit.

    Long story short, it ran with the carb kit (idled very well) but drove like crap. The RPM's would hang, and it would bog really bad...defiantly not an upgrade.

    I ended up putting all the stock parts back in and now it runs just fine. The carb kit was a waste of time.

    The trike now runs/drives great, but if I give full throttle at idle, it will stall. Half throttle is ok.

    When out in any gear, full throttle will not bog...just at idle a crack of the throttle will stall it. Is this just because the carb is not a CV carb?

    I noticed my stock needle is very worn at the tip. What does this affect? Its on the 3rd clip right now. If I moved it up or down a clip, would this help the bog? Does "up" a clip make it leaner, or "down" a clip make it leaner?

    Thanks!

  2. #2
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    Monroe MI
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  3. #3
    Join Date
    Feb 2008
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    Orange County California
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    726
    well, it has been my experience the replacement needle sucks,
    if the article did not help you, try this,
    be sure all your jets, and associated parts inside the ENTIRE carb are clean and free of any type of debris.
    Based on what you mentioned, try starting off with the needle clip at the very bottom. With the replacement needle, this should get you very close, depending on your elevation. fire it up, give it a somewhat higher idle, and let it warm up.
    Adjust the air/fuel mixture, a good baseline is turn it all the way in, and back out about a full turn and a half.
    Then when you find your seet spot with the air/fuel, bring the idle down to a rough 700-800rpms.
    Your goal is to achieve a snappy throttle!
    if it boggs down when you snap the throttle, the needle is way too much for the set up. At this point, re-use your old needle and start out at the 3rd possition. If it still boggs, then move it down and try again. Once you have it working correctly, then replace the plug and do the plug chop as stated in the attached article from MonroeMike.

    This is not going to get you perfect, I would refer more to the article than my own advice, but this should get you in the vacinity where you can start to play with it, dial it in, and get it perfect. I know it can be very frustrating, but take your time, and take comfort that once you get correct, it will be BadAss.
    1986 ATC250r
    1984 ATC70



  4. #4
    Join Date
    Feb 2009
    Location
    michigan
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    2,387
    probably sold you wrong carb kit.
    1985 ATC 250R
    . Team Red Trike

  5. #5
    unclejemima is offline At The Back Of The Pack Arm chair racerFirst time rider
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    Thanks guys.
    I will give the link a good read. I know carbs tuning is a fine art that I have yet to learn.
    I thought the carb kit was wrong too, but the kit was fully sealed with a Shindy part number that corresponds to a 86 ATC125M, so I might complain to Shindy and see what is up.

    Quote Originally Posted by Autophysn View Post
    ...be sure all your jets, and associated parts inside the ENTIRE carb are clean and free of any type of debris...
    Done and done. Carb cleaned with a good carb cleaner and compressed air.

    Quote Originally Posted by Autophysn View Post
    At this point, re-use your old needle and start out at the 3rd position. If it still boggs, then move it down and try again.
    According to my picture
    What is "move it down". You mean move the clip down (to #4), right, not move the clip up (#2) what would move the needle down. Always confusing

    By moving the clip down, it moves the needle up what in turn makes it run richer. Is that a correct statement?

    What does a worn needle affect? Will it make it run richer or leaner?

    Thanks!

  6. #6
    Join Date
    Apr 2008
    Location
    NW, IND.
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    842
    Needle up=richer, lets more fuel in.....Beets
    80' Honda CR80R
    78' Honda XR75
    77' Honda CT-70
    74' Honda CT-70
    75' Yamaha GT80 Enduro
    76' Kawasaki KZ900
    73' Kawasaki H1-500
    76' Kawasaki H1-500
    They always run best before they blow!
    Manuals: http://www.oscarmayer.net/atc/manuals/


  7. #7
    Join Date
    Feb 2008
    Location
    Orange County California
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    726
    My intention was to go down, as in try #4 and then #5
    1986 ATC250r
    1984 ATC70



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