Having trouble with build

Discussion in 'Motorized Bicycle General Discussion' started by neum5464, Sep 13, 2013.

  1. neum5464

    neum5464 New Member

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    I put a 66cc on a huffy Newport, haven't modified any parts. When trying to get the motor started, it does start and I can keep it running while holding the throttle, but it doesn't idle at all. As soon as I let go of the throttle it shuts off. I have adjusted almost every combination of settings on the carb from float to pin level and the idle doesn't seem to do anything either (even when it is all the way in). I tried turning the choke on while holding the throttle open and it killed the motor, so I think it is getting too much gas but I can't figure out how to change that without buying a new carb. Any input is helpful!

    On a side note, the kit came with a leaky petcock coming from the thread and with a little Teflon tape it has been dry so far. cheaper than ordering a new one.

    Thanks guys
     

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  2. crassius

    crassius Well-Known Member

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    I'd first try dropping the needle to its leanest position and see if I could adjust the idle screw for a good idle there.
     
  3. 2door

    2door Moderator
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    Looking at your photo I see you have the good old NT carburetor. That makes things easy as far as idle speed. There is only one external adjustment on the NT and that is the idle speed screw. Left side, the one with a spring under the head. Screw it in to increase idle speed and out to decrease.

    How is your clutch adjustment? Is the clutch fully disengaged when you squeeze the handlebar lever? If not that will prevent the engine from idling. You want little to no slack in the cable where it attaches to the clutch actuator arm on the engine.

    I'll also suggest you tighten the chain a little. 1/2" to 3/4" slack is where it needs to be. Yours is too loose.

    Let us know if these suggestions help.

    Tom
     
  4. crassius

    crassius Well-Known Member

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    DO NOT adjust the chain until you roll it through a full revolution to be sure that it is right at the tightest spot before you adjust it - if after adjusting at tightest spot, it sags badly at a looser spot, then realign your rear sprocket
     
  5. 2door

    2door Moderator
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    Good advice. If the rear sprocket isn't centered on the hub your chain tension will never be right. Thanks crassius.

    Tom
     

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