Kawi Carb Help (Mikuni BST34)

Discussion in 'The Garage' started by TexBiker, Mar 22, 2013.

  1. TexBiker

    TexBiker Been here awhile

    Joined:
    Oct 4, 2006
    Oddometer:
    815
    Location:
    East Texas
    I'm having an issue with my '01 Super Sherpa. It starts fine, but almost immediately, fuel starts flowing from the drain at the bottom of the bowl and from one of the vent lines that drain out the back. After a few minutes, the engine sputters and dies. Cranks right back up and repeats itself.

    I'm not great with carbs (as if that needed to be said), but I'm guessing it might be a stuck float? Tapping the carb with a screwdriver didn't help. Neither did loud cursing. Percussive maintenance and profanity are usually the first two steps I take to these sorts of issues.

    Before I take the carb off the bike, I was hoping to get a bit more input. Thanks in advance.
    #1
  2. baloneyskin daddy

    baloneyskin daddy bikaholic

    Joined:
    Oct 21, 2009
    Oddometer:
    2,177
    Location:
    southcentral PA.
    Most certainly a problem with the float or needle and seat,either stuck,broken or a piece of debris stopping the needle fro closing.
    #2
  3. Sam il Cinghio

    Sam il Cinghio dirty noob

    Joined:
    Mar 22, 2013
    Oddometer:
    56
    Location:
    Italy
    Hi Tex,
    think I can try to help you but you have to be patient with my english :wink:

    In my opinion you can find your problem on the float.
    Then, turn over the carbs and dismount the float chamber cover: now you can see the float.
    [​IMG]
    Dismount (be carefully!) the float and the float valve.
    Check if the float are damaged or perforated.
    Inspect the needle valve for signs of wear or damage. Ensure the needle valve tip is undamaget and its sprimg-loaded rod operates correctly (renew if necessary).
    [​IMG]
    Clean the carbs and above all the needle valve hole.
    Re-mount float and needle valve.
    Check the float heigt (I don't know the exact measure, you must find it... it is about 15mm): ensure the needle valve rod is not compressed at all and measure the distance from the carburettor surface to the base of the float. Adjustment is made by carefully bending the float tang.
    [​IMG]

    Obviously, I suggest to take the opportunity for clean ALL carburetor ;)
    #3
  4. FAW3

    FAW3 Old wanderer

    Joined:
    Mar 13, 2009
    Oddometer:
    690
    Location:
    No.VA.
    "I'm not great with carbs" could be my sig line too...

    I've had some fun with similar units on several bikes over the years. Here are some suggestions:

    Check out you tube...there are several sources of good "how to" vids on cleaning/checking out simple MC carbs. There are also "how they work" vids that help you understand whats going on in these devices of the devil.

    Get a parts diagram & parts list of your specific carb. When comfortable....partly dissamble carb and clean, clean, clean....wear safety glasses when spraying.

    Order a parts kit for your bike...might as well have it on hand. If it's been a few years, or you don't know...start by installing the kit...then you know your at least starting from a good start point.

    Avoid the temptation to mod carbs part by part...install a full kit.
    #4
  5. TexBiker

    TexBiker Been here awhile

    Joined:
    Oct 4, 2006
    Oddometer:
    815
    Location:
    East Texas
    Thanks guys. I've replaced the jets (years ago), but never fiddled with the floats in this carb. Guess I need to reacquaint myself with the little thing later today.

    I appreciate the advice. I hope it just needs a good cleaning. I hate waiting for parts! :)
    #5
  6. Danjal

    Danjal Insert wit here.

    Joined:
    Oct 9, 2011
    Oddometer:
    2,755
    Location:
    Location,Location
    I assume it has a vac operated petcock?
    #6
  7. TexBiker

    TexBiker Been here awhile

    Joined:
    Oct 4, 2006
    Oddometer:
    815
    Location:
    East Texas
    Turned out to be a dirty needle valve. A few shots of carb cleaner and all is well now. Thanks to everyone!
    #7