ktm 530 running lean

Discussion in 'Thumpers' started by peman, Sep 27, 2020.

  1. peman

    peman Been here awhile

    Joined:
    Jun 16, 2012
    Oddometer:
    175
    Location:
    Brisbane, Australia
    Hi everybody,
    i need help with this bike, 2010 ktm 530 I've had this bike for almost four years and early on i fitted a jd jetting kit and the bike ran very well, then just over a year ago i put a new wossner high com piston in and had to raise the needle one clip and has ran good even dynoed it and was just slightly rich at the top end of the rev range, until a few months ago when i found the bike would change in it's power level, it would feel gutless then it wouldn't etc and was getting worse, until i stripped the carb down and found the needle clip had worn through leaning the bike out so i rebuilt the carb and fitted another needle ocemn and 162 main jet, a proven combination.

    then two rides later it died, i'm very mechanically inclined but between work and life i got a bike shop to look at it and they found the piston fried! they blamed the needle for being too lean but i checked it out and it's almost a perfect match to the red needle from the jd jetting kit except for the tip which is why the smaller main jet.

    so they serviced the head, fitted a red needle back 175 main jet, new piston and running and see you later.

    i ran it in the bush and it was pushing coolant out..rang the shop and they said the head was no good, ok i found another one and when i took the head off the piston and head were scorched!!

    fitted the new second hand head and 20 min later the bike was dead, it started to fry the new head and the piston was done, so i got the head redone, got another barrel and got it re-coated and new vertex high comp piston and run the bike in and i checked the plug and it's ghost white!! i swapped the jetting to another carb and ran it again and the plug is still ghost white.

    i raised the needle one clip and ran it again and checked it an hour later and it's still ghost white, i'm running it richer then ever and the plug tells me it's too lean, the only symptom it has is it doesn't wind out 5th and 6th like it used too, i have pics if needed but i don't understand how it's changed when it was fine with the jetting the way it was, can it be ignition? using the same fuel,
    same spark plugs, the problem seems to crept into it, any idea's thoughts, questions just ask, it has cost me a lot of time, money and sanity please help.
    #1
  2. Navin

    Navin Long timer

    Joined:
    Sep 22, 2009
    Oddometer:
    28,959
    Intake manifold leaking?
    #2
    Bitingdog and Bultaco206 like this.
  3. peman

    peman Been here awhile

    Joined:
    Jun 16, 2012
    Oddometer:
    175
    Location:
    Brisbane, Australia
    will check that now. thanks
    #3
  4. peman

    peman Been here awhile

    Joined:
    Jun 16, 2012
    Oddometer:
    175
    Location:
    Brisbane, Australia
    checked for air leaks with acetone and no reaction, i raised the needle one clip and run it and the plug was still white so i've raised it again and it's definitely more responsive so i'll be doing some test and tuning this Saturday in the national park, absolutely puzzling behavior.
    #4