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.

Popping noice from exhaust

Discussion in 'XJ Technical Chat' started by Wendall79, Jun 25, 2007.

  1. Wendall79

    Wendall79 New Member

    Messages:
    19
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Des Moines, IA
    When driving at street or highspeed and back off on the throttle, the engine/exhaust makes a popping noice (especially if I go down a gear and the engine revs up). They are individual "pops" that are a second or two aprt, not a pa-pa-pa-pop noice. Any ideas what causes this and how it could be fixed?
     
    Wendall79, Jun 25, 2007
    #1
  2. KiwiXJ750D

    KiwiXJ750D Member

    Messages:
    587
    Likes Received:
    4
    Trophy Points:
    18
    Location:
    New Zealand
    Lean backfire?
    Make sure boots between Engine and Carbs are airtight and not cracked. Shoot WD40 on them at idle and see if the idle changes.
    Standard exhaust and filter?
    Clean air filter properly installed?
    Synced and tuned carbs?
    Have a look at your plugs:
    http://www.dansmc.com/spark_plugs/spark ... talog.html

    Also while you are working on the bike:
    Check alternator brushes are within spec. Battery OK. Check general condition of wire connectors.
     
    KiwiXJ750D, Jun 25, 2007
    #2
  3. Wendall79

    Wendall79 New Member

    Messages:
    19
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Des Moines, IA
    Well, here is what i know so far:
    The carbs were just cleaned/rebuilt at a Yamaha shop (I assumed they were synced and tuned properly). Valves were adjusted as well. I hava a standard 4-into-1 exhaust and the air filter is new and installed correctly.

    I'm not sure of the condition of the battery or alternater. But - could you expain how this my contribute to the popping noice?

    As for the popping noice, it mostly happens at RPMs above 3000 or so. Example: coasting down a steep hill in first or second gear.

    I just tried the WD-40 trick. I though I may have noticed an ever so slight change in the idle/engine sound, but I can't be sure. I'll have to again (do I have let it burn/smoke off before I can try this again?).

    Haven't checked the spark plugs yet.
     
    Wendall79, Jun 25, 2007
    #3

Share This Page