Home Forums 2-Cycle Racing Problems starting yamaha kt100

This topic contains 11 replies, has 6 voices, and was last updated by  Omar Calixtro 3 years, 4 months ago.

  • Author
  • #49553

    Omar Calixtro

    I have a yamaha kt100 and I have recently installed a clutch on it. The thing is the kart started just fine on direct drive and now it won’t start with a clutch. It does pump fuel. Also if I choke the wb3a carb the engine starts then turns off. If I don’t choke it the engine doesn’t turn on at all. Am I doing something wrong? It would really help if someone gave me the steps on how to turn on a kart with a clutch.

  • #49555

    Peter Zambos

    It’s really simple. Engage starter shaft. Activate starter. Blip throttle. Disengage starter. You might have to choke the intake for a second if you just put a fresh carb on it.
    If you have to do anything else, then something else is wrong. Does the clutch and axle spin easily while the kart is on the stand?

    • #49557

      Omar Calixtro

      The clutch and the axle spin just fine.

  • #49558

    TJ Koyen

    So it starts when you choke it? Do you then keep giving it throttle to keep it running and it still dies?

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com

    • #49559

      Omar Calixtro

      I haven’t tried going full throttle. I say I go about medium throttle. Should I give full throttle or very little throttle?

  • #49575

    tony zambos

    Was anything else done to the motor besides installing the clutch?
    How did you hold the crankshaft stationary while tightening the starter nut on the clutch?

    LAD Specialties customer / tony kart / rotax / kt100

    • #49576

      Omar Calixtro

      Tony, nothing else was done besides installing the clutch. I could check the carb. But I doubt thats the problem because if I choke the engine fuel does pump.

      • #49619

        Omar Calixtro

        Also I am using the inbuilt fuel pump on the walbro wb3a.

  • #49609

    Walt Gifford

    Clean the fuel screen and put in a new pumper. Also could be a fouled plug from running rich on the stand.

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #49617

    Omar Calixtro

    I also noticed just now when I tried to start it again that the fuel had trouble getting up to where the fuel going in the carb. The fuel had problems going up once I stopped choking the engine


  • #49624

    Patrick Haney

    I had the exact same problem. When I cloaked the engine, the fuel would reach the carb. As soon as I took my hand off the intake, the engine would stall.  Problem? Fuel tank vent was clogged.

    • #49635

      Omar Calixtro

      Thank you patrick I will take a look at the fuel tank vent later.

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