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Hard to start(Video)

Discussion in 'The Garage' started by newclind, Nov 15, 2023.

  1. newclind

    newclind XS400 Member

    Hi, I have 1980 xs400 special and I have been trying to fix my first bike. I did carb cleaning, float height, valve adjustment, new battery, new fuel, new intake boot, and new foam filter.

    This bike used to run semi-consistently with cracked intake boot so I changed to new boot couple days ago.

    Yesterday, I tried so hard to make it run by adjusting mixture screw for an 2 hours and it somehow ran without a choke(?). It ran really good once the engine was hot. Starts back up with no problem.

    Now I tried to run it again today and its doesn't want to idle. It starts but dies in 2 seconds or so. I have video that has the sound of the bike. It acts like its lean but I checked the sparkplug yesterday after it ran for 15min and the plugs looked pretty good.

    Should I try adjusting mixture screw more?

    TLDR: Bike has hard time cold starting with or without choke. Bike cold started without choke yesterday and ran really good.

  2. CaptChrome

    CaptChrome XS400 Addict Top Contributor

    Sounds like you have a fuel issue. When I kick start mine, I usually "prime" the cylinders with mix first to make it easier to start:
    1. turn fuel petcock on
    2. pull out choke all of the way
    3. without turning on the key, give the bike 3 kicks to pull some fuel/air mix into the cylinders
    4. if it is warm outside, I set the choke to half, if it is cold, leave it where it is.
    5. turn on the ignition and make sure the kill switch is in run. Then kick the bike to start it. Mine fires the first or second time.
    newclind likes this.
  3. newclind

    newclind XS400 Member

    Thanks, I give this sequence a try.
  4. newclind

    newclind XS400 Member

    After many tries, I've learned that my vacuum hose had some worn out clamps and my carb liked 6 turns out on the mixture screw. It runs with first kick now. Thank you for help.
  5. brookeadams13

    brookeadams13 XS400 New Member

    Glad to know that it runs well, and you find your way.

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