Another Newbie Question - Engine Won't Idle, always accelerates

Discussion in 'Motorized Bicycle Trouble Shooting' started by VTHokie, Jan 4, 2013.

  1. VTHokie

    VTHokie New Member

    Joined:
    Dec 18, 2012
    Messages:
    42
    Likes Received:
    0
    I have a Chinese 2 stroke w/ NT carburetor

    So I finally got my bike running, got a new coaster brake and got the rear wheel balanced and trued.

    But now, when the bike is running, it's constantly moving forward. In fact, it's accelerating. The only way to stop it from trying to accelerate is by slowly closing the choke (pulling the choke lever upward), but this turns off the engine. If I squeeze the clutch, it won't idle, it just starts vibrating harder and tries to move the chain still. AND, the throttle doesn't seem to have an effect on the acceleration of the bike - I know I installed it in the carb correctly because I see the black throttle cylinder slide up and down when I move the throttle.

    What's the deal? Thanks for your help in advance
     
  2. BikeBerryJen

    BikeBerryJen Engine Diva

    Joined:
    Oct 25, 2012
    Messages:
    45
    Likes Received:
    0
    Hi VTHokie! Have you tried tuning your carburetor? When you install an engine (before your first ride) you would need to tune your carburetor. Also, check to make sure that your throttle is installed correctly.

    http://www.youtube.com/watch?v=XAaKSII_vbo

    When adjusting your Jet Needle, please remember to turn your idle screw one and a half turns for proper tuning!

    .wee.
     
  3. VTHokie

    VTHokie New Member

    Joined:
    Dec 18, 2012
    Messages:
    42
    Likes Received:
    0
    Hey there, I figured out the acceleration problem - a zip tie I used to secure the throttle cable created a kink in the neck of the cable, and wouldn't allow it to go up and down in the carburetor. That's now resolved and the throttle is functioning properly. I also tuned the carburetor for a richer mixture (I couldn't get the engine to start with the 16:1 ratio). The engine ran okay at low speeds, but when I revved it all the way, it only got up to about 15-20 mph and was reeeally loud.

    And, I still can't get my engine to idle - I want to run the engine for like 20 minutes to break it in a bit, but every time I squeeze that clutch, it shuts off unless I have the throttle fully revved.
    The engine also shuts off if I try to close the choke

    Any suggestions? Thanks!
     
    #3 VTHokie, Jan 4, 2013
    Last edited: Jan 4, 2013
  4. UVsaturated

    UVsaturated New Member

    Joined:
    May 15, 2008
    Messages:
    140
    Likes Received:
    2
    Can I ask how you 'tuned' the carb for a rich mixture? Rich and lean in regards to mixture is the ratio of air to fuel which is about 14:1 for a clean burn and 12:1 for a rich mixture. 16:1 sounds like a mix for a fuel to oil, which would be 8oz oil to 1 gal of fuel. Which one are you talking about in this context?
     

Share This Page