Carby New carb, bike will NOT start

Discussion in '2-Stroke Engines' started by willfargo, Oct 12, 2011.

  1. willfargo

    willfargo Member

    Just installed a 1st gen CNS carb on my 66cc. it was running fine with the stock, but i cant get it to fire at ALL with the CNS carb. What can be causing this?
     

  2. Lazieboy

    Lazieboy Member

    carb

    Can you hear the slide inside carb move freely up and down when you twist throttle. check for air leaks and im sure u did alwready but check spark. good luck your answer will come.
     
  3. willfargo

    willfargo Member

    Ya its all pretty much kosher! i just cant get it to do ANYTHING
     
  4. motorpsycho

    motorpsycho Active Member

    are you sure that gas is flowing into the float bowl?
    it's possible that the main jet is blocked with some kind of debris.
     
  5. willfargo

    willfargo Member

    I can take it apart again but the jet is brand new!
     
  6. willfargo

    willfargo Member

    Well it leaked gas all over the garage floor last night >.< im not sure if the bowl was even full, when i tipped it over after i took it off, not a whole lot of gas leaked out. if the bike wouldnt start while this carb was on, and it leaked... could those 2 things be related? and what might be causing this? i replaced all the screws and the jet and gaskets and float with the kit from Gasbikes, so everything is new!
     
  7. bideronit13

    bideronit13 Member

    I'm thinking about it in the mean time can you show some pictures? Can I see some pictures?

    I'm thinking vacuum.
    Check out this video and how this guys got it rigged for vacuum
    Stop the video 16 seconds into it and you get an excellent look.
    .


    http://www.youtube.com/watch?v=w_F7C2k7xNg
     
    Last edited: Oct 14, 2011
  8. willfargo

    willfargo Member

    aha! well thats definitely not how the vacuum hoses were set up. I didnt get this carb new, it came with a bike i had purchased a while back. if i didnt have it hooked up that way, would it keep it from running correctly? i'm gonna go down and take some pictures in a moment
     
  9. willfargo

    willfargo Member

    Here is how its currently setup
     

    Attached Files:

  10. bideronit13

    bideronit13 Member

    Did you try hose to carb combo's it not the same as the video
     
  11. willfargo

    willfargo Member

    I havent changed them I will give it a whirl tomorrow and see what happens
     
  12. willfargo

    willfargo Member

    so i switched the vacuum lines to fit what they were int hat video that was posted. However, im looking down the hole for the slide, and i dont see the small bump thats supposed to keep the slide in the correct position
     
  13. bideronit13

    bideronit13 Member

    If you be more specific or take a picture I'd be glad to help.
     
  14. willfargo

    willfargo Member

    When the slide is placed into the cylinder, there is channel in it, then there is a bump on the side of the cylinder to keep the slide from turning in circles. My other carb has it, the cns does not
     
  15. bideronit13

    bideronit13 Member

    Sound like the throttle cable or cables need to be mounted is all.
     
  16. bideronit13

    bideronit13 Member

  17. lazydog

    lazydog Member

    It should, if your talking about the little brass nubin.

    Try this (very small turns)
    Take all the hoses of the silly thing (except fuel of course.) Plug the hole on the back of the air intake filter(keep dirt and **** out)

    Tighten the air/fuel screw and loosen the idle screw (start here, reset the carb)

    IF it wont start give the air/fuel a little turn (1/8 turn increments), do this till it starts

    After it's Kinda running (have to pump the throttle to keep it running) - slowly close the idle screw till it idles and sounds good.

    Run around a few minutes and check the plug color and adjust air/fuel as needed. Only use the idle adjust to keep it running smooth.

    The new CNS is very badly tuned from the factory(not even close) Basically reset the carb and start over.

    Mine runs great, better then anything else I run across NT, Speed, dellorto, I just finished reverting to all the STOCK parts tonight to make a video this weekend.
     
    Last edited: Oct 14, 2011
  18. motorpsycho

    motorpsycho Active Member

    just because it's brand new does not mean that there can't be a small peice of crud in the jet.
     
  19. motorpsycho

    motorpsycho Active Member

    if it leaked gas all over then the float may be stuck or way out of adjustment. This woudl cause the needle & seat to stay open too long and overflow the bowl. Gas will leak out of the overflow tube and on to the floor.
    In your pics i think you have the overflow tube hooked into the vaccuum port.
    the overflow tube should just hang down under the carb and not be connected to anything (other than the overflow pipe on the carb).
     
  20. lazydog

    lazydog Member


    You left the fuel valve open didin't ya, I do it all the time too.
     
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