Bike Won't Start

Discussion in 'Photos & Bicycle Builds' started by hserro1221, Mar 19, 2015.

  1. hserro1221

    hserro1221 New Member

    Hi, I just got a 80cc bicycle engine kit. I assembled the whole thing onto a beach cruiser. There is gas in the bowl and I have a spark but the bike won't start. If I give it full throttle while I pedal it will pop on and off (just for a moment) but won't stay running. Any ideas what's wrong with it?

  2. Timbone

    Timbone Active Member

    Don't give it full throttle! Sounds like it wants to run, probably just needs the right mix of fuel and air flow. Check your fuel flow - make sure there isn't a vapor lock or anything hindering flow. And just barely move the throttle input. Too much air may be preventing the engine from getting a good pop.

    It's as much art as science!
  3. hserro1221

    hserro1221 New Member

    How many screws out should my air screw be?
  4. Timbone

    Timbone Active Member

    Idle screw on the NT carb? 3 1/2 turns out is the rule of thumb.
  5. KCvale

    KCvale Motorized Bicycle Vendor

    Get real torque wrench and tighten your head 20#, 5# at a time in an X pattern.
    It takes Spark, Fuel, and Compression to run, you have 2 of the 3.
  6. dougsr.874

    dougsr.874 Active Member

    I assume this is a new place choke lever in full up position...pedal & try to start,,,then lower choke lever to full down position..then pedal & try to start again..chances are it will start then...after engine is broken in or is warm choke will not be necessary