1. Some members were not receiving emails sent from XJbikes.com. For example: "Forgot your password?" function to reset your password would not send email to some members. I believe this has been resolved now. Please use "Contact Us" form (see page footer link) if you still have email issues. SnoSheriff

    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.

Chirping after vacuum sync

Discussion in 'XJ Technical Chat' started by PilotSmack, May 1, 2014.

  1. PilotSmack

    PilotSmack Active Member

    Messages:
    372
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Calgary, Canada
    Hey guys,

    So her idle was pretty wonky, so I did a running vacuum sync. 1 and 2 were waaay out, fixed that, but now there is a chirp at idle that sounds like it's coming from carb #1. It changes with the engine speed, and only does it at <3000rpm. First thing I thought was a vacuum leak, or buggered shaft seals. Held an unlit propane torch by all 8 boots, and by all shaft seals, no change in idle speed. Ideas?
     
    PilotSmack, May 1, 2014
    #1
  2. Xjrider92117

    Xjrider92117 Active Member

    Messages:
    994
    Likes Received:
    136
    Trophy Points:
    43
    Location:
    San Jose Ca
    More info pls. Valves in spec. Right.
     
    Xjrider92117, May 1, 2014
    #2
  3. TIMEtoRIDE

    TIMEtoRIDE Active Member

    Messages:
    4,686
    Likes Received:
    11
    Trophy Points:
    38
    Location:
    Clermont FL near Orlando
    TIMEtoRIDE, May 1, 2014
    #3
  4. PilotSmack

    PilotSmack Active Member

    Messages:
    372
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Calgary, Canada
    Valves in spec, full rebuild of the engine, carbs church clean, new intake manifold gaskets, rebuilt petcock, still running the old spark plugs and wires but they're in spec and she colortuned just fine, another sync after that didn't take much effort. I also found that if you accelerate the engine sharply it goes away, but then continues once it tries to idle. Gunna clean out the YICS ports and go for a test ride.
     
    PilotSmack, May 1, 2014
    #4
  5. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,097
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    get a hose that you can hold to your ear and move the other end around, see if you can find the chirp.
    you might have a critter in the airbox :)
     
    Polock, May 1, 2014
    #5
  6. rocs82650

    rocs82650 Well-Known Member

    Messages:
    2,663
    Likes Received:
    356
    Trophy Points:
    83
    Location:
    Middle Tennessee
    are the exhaust nuts tight to spec? did you replace the crush washers?
     
    rocs82650, May 1, 2014
    #6
  7. PilotSmack

    PilotSmack Active Member

    Messages:
    372
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Calgary, Canada
    Nuts are at spec, and yup, new exhaust gaskets, but that sound is definitely coming from carb 1. After another 50k joyride, it will still do it about half the time at idle, will do it at any engine speed decelerating, but it won't do it if the engine is under load (ie, 2500rpm accelerating in a turn). Holds an idle just fine though. Maybe something in the top end carb 1 isn't as clean as I thought it was?
     
    PilotSmack, May 1, 2014
    #7
  8. quebecois59

    quebecois59 Well-Known Member

    Messages:
    2,285
    Likes Received:
    114
    Trophy Points:
    63
    Location:
    Waterloo, Quebec, Canada
    I suppose you checked if the vacuum rubber cap is in good shape and if the carb hat is properly tightened?
     
    quebecois59, May 1, 2014
    #8
  9. PilotSmack

    PilotSmack Active Member

    Messages:
    372
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Calgary, Canada
    The caps are on there good and tight, but even if I take the cap off of #1 it still chirps. I'm gunna lift the tank and check out the top end of #1 tomorrow.

    Btw, for those members who haven't done a vacuum sync and colortune, DO IT NOW!! Night and day difference, way smoother, more responsive, and since all 4 were running rich, probably gunna save me some gas.
     
    PilotSmack, May 1, 2014
    #9

Share This Page