1. Husqvarna Motorcycles Made In Sweden - About 1988 and older

86 400XC jetting considerations if overboring

Discussion in 'Vintage/Left Kickers' started by Quimo, Mar 22, 2021.

  1. Quimo Husqvarna
    B Class

    Husqvarna Motorcycle:
    1986 XC400
    Other Motorcycles:
    72 Triumph Bonneville 650, 13 YZ450F
    If I’m going to bore to 83.5 or 84 (second or third over) on a 86 400XC do I need to consider changing from stock jetting?
  2. 2premo Husqvarna
    Pro Class

    Location:
    Northern NV
    Husqvarna Motorcycle:
    98 WR360, 1987 WR430, 1988 XC430
    Other Motorcycles:
    Sherco 300, 2002 KTM 380EXC
    no, not enough difference
  3. ruwfo Administrator

    Location:
    NJ
    Husqvarna Motorcycle:
    1980 390CR, 1982 430CR, 1984 400WR
    Other Motorcycles:
    1985 250XC, 2016 FJ-09
    I agree
  4. motomwo Husqvarna
    AA Class

    Location:
    Imbler Oregon
    Husqvarna Motorcycle:
    Many vintage big bore and automatics
    My question would be why do you need to over bore the cylinder? If it because it seized then maybe jetting changes are required or is there another problem such as bad main seals or other case leakage?

    Marty
  5. grouty Auto Lover ...

    Location:
    South West UK
    Husqvarna Motorcycle:
    78 390WR, 78 390 AMX, 500 Humph
    Other Motorcycles:
    works 73 CCM 520, another 73 CCM520
    Maybe it's just worn out Marty.
    My 390WR wore out the bore eventually.
  6. motomwo Husqvarna
    AA Class

    Location:
    Imbler Oregon
    Husqvarna Motorcycle:
    Many vintage big bore and automatics

    Hi Grouty,
    Yes very true and hopefully that is the case, just wore out.

    Marty
  7. steadydirt Husqvarna
    AA Class

    Location:
    Ontario
    Husqvarna Motorcycle:
    2007 2002 wr 250 1994 wxe 250
    Other Motorcycles:
    fj 1100 cb500 cb350 rt 200 xs 650
    wonder if you could sleeve it. understand a bump in power from better ring seal.