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.

Throttle slow to return from 5000 rpm

Discussion in 'XJ Technical Chat' started by DanP, Jul 3, 2007.

  1. DanP

    DanP Member

    Messages:
    107
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Newmarket, Ontario
    1981 xj650 Maxim

    Carbs cleaned, mixture screws set to 2 and 3/4 turns. Bench Sync'd the carbs. She starts and idles fine. There's a small flat spot at the beginning of the throttle. It revs up, but takes a few seconds to come down back to idle. When riding, the throttle still stays up there unless I use the engine to brake, pretty scary actually. It also spudders.

    So, should I buy a colortune, and if so what size? Is there anything I should check for, and is there anything I'm missing?
     
    DanP, Jul 3, 2007
    #1
  2. RickCoMatic

    RickCoMatic Well-Known Member

    Messages:
    13,842
    Likes Received:
    67
    Trophy Points:
    48
    Location:
    Massachusetts, Billerica
    Air leaks
    Tight throttle cable
    Weak return spring (Missing spring)
    Pilot Mixture Screws too Rich
    Diaphragm Piston(s) Sticking within Bores
    Throttle Flys loose
    Bad Sync
    Enrichment Plungers not seating when closed.

    Real dirty linkage
    Swollen Butterfly shaft seals.
    Throttle Cable needs some lube.
     
    RickCoMatic, Jul 4, 2007
    #2
  3. BlueMaxim

    BlueMaxim Active Member

    Messages:
    1,986
    Likes Received:
    4
    Trophy Points:
    38
    Location:
    Central Mississippi
    Most times the carbs need a colortune and sync to fix this. Air leaks can do this so check the carb boots for leaks by spraying some WD-40 around them and listen for a change in engine RPM. You will need the 14mm colortune. These is an annual Southern Ontario carb clinic where you can go and get the colortune and sync done. I don't when it is scheduled but will try to find out and post the info.
     
    BlueMaxim, Jul 5, 2007
    #3
  4. DanP

    DanP Member

    Messages:
    107
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Newmarket, Ontario
    Hey Guys,

    It's looking good. I've got the throttle down and controlled now. Seems to be returning very quickly. Looks like I'm almost dialed in. When my colourtune plug comes in, I'll get it set perfect, and it should scream!!

    Thanks for all your help.
     
    DanP, Jul 5, 2007
    #4

Share This Page