Honda CT110 - will not idle

Discussion in 'The Garage' started by TrappedAtWork, Dec 12, 2009.

  1. TrappedAtWork

    TrappedAtWork No Longer Trapped!

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    Hi All,

    Spent the day in the shed (sorry Cob "racing workshop"), so overall a good day.

    We have a honda CT110 postie, that we thought had a sticking throttle cable, so set about trying to fix it today.

    We cleaned the carbie out, took the bowl off and blew out the jets, all seemed ok. Reassembled with no spare parts. Everything appers to be normal. :wink:

    The problem:

    We can kick start the engine, with just a little throttle to get it going.

    Idle will not hold the engine, therefore we must hold the throttle on just slightly, to get it to idle.

    After reving engine it will return down to near idle speed, the die if the throttle is not held on. After reving a few times in a row and closing the throttle the revs continue to rise, until the engine seems it is about to explode. (They make a lot of noise at 15000 revs :freaky )

    We unscrewed idle screw a turn or two and the revs fall, the engine will die if the throttle is not held on just slightly.

    We also tried to take out the free play in the throttle cable, near the twist grip.

    The throttle cable does not appear to be sticking.

    This is a very small slide carbie with a long needle through the middle of the air flow chamber.

    Air filter is clean, added fresh fuel to the tank.

    Box of matches standing by. :kboom


    Any thoughts gratefully accepted...


    Cheers,

    TAW
    #1
  2. showkey

    showkey Long timer

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    The pilot jet (also know as the slow jet is plugged) it is a very very small hole and you should hold up to the light to check, you can pass a small wire through but be careful not to inlarge or ream the jet larger.

    This asumes the air screw is open about 2 turns as a starting point.
    #2
  3. mcma111

    mcma111 Long timer

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    Did you put the slide in backwards???
    #3
  4. Cogswell

    Cogswell Spudly Adventurer

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    That can cause the problem as well as a too tight intake valve clearance.

    Mike
    #4
  5. showkey

    showkey Long timer

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    Not really possible and still have run off idle.....the slide has a slot and the slide bore has a pin they must line up for the slide to be in the down or closed position.
    #5
  6. showkey

    showkey Long timer

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    #14 is the pilot or slow jet

    [​IMG]
    #6
  7. trail90man

    trail90man Adventurer

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    I have about 30,000 miles experience on trail 90s. It sounds like you should check the spark advance. This is a mechanical unit behind the points up on the left side of the head. if this sticks, it is impossible to set the idle. You can wash the advance out with some wd-40 without removing or re-setting the points and see if that allows you to set the idle. if it helps the real solution is to remove the advance unit and clean and grease it.

    Kyle :-)
    #7
  8. vtwin

    vtwin Air cooled runnin' mon

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    #8
  9. TrappedAtWork

    TrappedAtWork No Longer Trapped!

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    Thanks, I believe this this the problem.

    [​IMG]

    From memory, I think the outlet from the Pilot screw (circled in red) is blocked, I will pull it apart and have another look. I did not really pay attention yesterday.

    I'll take a look as soon as I can get to the racing workshop.
    #9
  10. TrappedAtWork

    TrappedAtWork No Longer Trapped!

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    Cheers but I don't believe so, there is only one way that it goes in.
    #10
  11. TrappedAtWork

    TrappedAtWork No Longer Trapped!

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    Thanks to showkey.

    The postie now idles.... Cheers...

    :freaky
    #11
  12. tundrawolf

    tundrawolf Desert Rat V Star

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    I used oil to lubricate the advance assembly. Should I use grease? It seems to have significant resistance with grease. Does it matter?
    #12