1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Carb confusion IDK

Discussion in 'XJ Technical Chat' started by Joe34, May 28, 2021.

  1. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    So tore down more carbs after they been sitting around for ever. Did a through cleaning.
    I Put new dyna coils on new wires, because I though the coils was the issue. So the carbs are on, everything is synchronized, wet sync as well. All good.
    One thing new that's happening is, when I prime it has comes out the overflow on 3 and 4.
    Bike idles fine takes gas great in neutral but taking off in first has a small hesitation. After I'm on the gas it's fine, tons of pull.

    Checked plugs 1,2 and 3 are a nice tan, number 4 is black chalk.

    Compression is good all across. When I mess with the pilot mixture it seems to do nothing on where I set it. On the number 4

    Also has an amazing spark but when it's running and I pull number 4 wire off plug there's no change. The rest does change.

    I'm lost. Been at it for days, any advice and knowledge would be great thank you.
     
  2. StahlMaster

    StahlMaster Active Member

    Messages:
    146
    Likes Received:
    33
    Trophy Points:
    28
    Location:
    Southgate, Michigan
    Swap the plug and see if the issue follows?
     
  3. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    Yep did the same, also tried multiple TCI's
     
  4. Huntchuks

    Huntchuks Well-Known Member

    Messages:
    950
    Likes Received:
    395
    Trophy Points:
    63
    Location:
    East Rochester, NY
    Stuck float needle on carb 4 also?
     
  5. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    Checked float seems fine. Never checked needle but never touched it also.
     
  6. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
  7. Huntchuks

    Huntchuks Well-Known Member

    Messages:
    950
    Likes Received:
    395
    Trophy Points:
    63
    Location:
    East Rochester, NY
    This seems to indicate float needle(s) stuck open.
     
  8. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    Yes wet set is on par. And I did reuse them, the rack was a full rebuild I did few years ago.
     
  9. tabaka45

    tabaka45 Well-Known Member

    Messages:
    2,348
    Likes Received:
    494
    Trophy Points:
    83
    Location:
    Brunswick, Georgia
    If gas is flowing out on Prime it would seem to me to indicate a needle valve not sealing. When I wet set mine I let them sit for about an hour and moved them around a little bit. They didn't leak at first but over time they did. Did that several times with the same results. Replaced my rubber tip needles and seats with solid brass needles and seats (from Chacal) and that solved my problem.
     
    k-moe, Jetfixer and Joe34 like this.
  10. Jetfixer

    Jetfixer Well-Known Member

    Messages:
    3,173
    Likes Received:
    1,485
    Trophy Points:
    113
    Location:
    Nothern Indiana
    Did you look at the tip of the needle if it has a groove and is stiff , this can cause issues like not shutting off fuel flow when engine shut off and fuel left on PRI . I just went through a carb problem with my JCB ...If you have the carbs off check slides , I had one that would not go up all the way , and another that dropped with no resistance, yes bike ran fine at idle , but you had to stay on throttle and felt like it was running on three cylinders. Fixed it with another slide and one slide was not fully in the groove , now bike runs great .
     
    k-moe likes this.
  11. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    Just found out the if I take the little sync plug cap off of intake boot almost instantly comes out of its issue.
     
  12. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    Took off carb checked floats and needles. Still doing same thing. Unless I take this cap off the intake boot it runs better. Makes no sence
     
  13. Jetfixer

    Jetfixer Well-Known Member

    Messages:
    3,173
    Likes Received:
    1,485
    Trophy Points:
    113
    Location:
    Nothern Indiana
    Did you do a clunck test on the slides? Pull them up fully see if the slide drops fast or drops slowly...slowly is what you want.
     
  14. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    They all drop evenly at a slow pace
     
    Jetfixer likes this.
  15. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Which carb?
    Removing that plug leans out the mixture.
    It seems to me that if it's the same carb that gives you a black sooty plug, then that carb is setup to be too rich.
    Did you do anything to the idle mixture screws?
     
    Jetfixer likes this.
  16. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    Carb 4 every time. I'm confused because that carb is set up the exact same as the other 3. I can turn the idle mixture screw all the way In. Small difference, all the way out no difference.
    Same wet set for floats, same dry measurements. Even running sync is straight across the bord with my carb tune.
    Only thing I can think of is that the wrong pilot jet is in.
     
    Jetfixer likes this.
  17. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Check the air jets first.
    [​IMG]
     
    Jetfixer and Joe34 like this.
  18. ManBot13

    ManBot13 Well-Known Member

    Messages:
    1,592
    Likes Received:
    176
    Trophy Points:
    63
    Location:
    Fairfax, VA
    You are just letting in a bunch of air, which makes it run better because it burns some of the fuel that is flooding #4. This is not a solution.

    All four carbs are not “set up” the same if #4 flat bowl is overflowing. Fix one problem at a time, and the first problem is there. Messing with mixtures or sync down stream won’t get it running right, you’re just covering up the problem. And you’ll need to redo all of that once you fix the float/needle.
     
    Jetfixer likes this.
  19. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    It's not overflowing now on prime as I fixed the float needle.
    Still not getting enough air.
     
  20. Joe34

    Joe34 Active Member

    Messages:
    250
    Likes Received:
    93
    Trophy Points:
    28
    Location:
    Halifax nova scotia
    And also does the pilot jets have two different sizes with same size number stamped ??
     

Share This Page