1. 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    WR = 2st Enduro & CR = 2st Cross

All 2st Jetting Chat - Need Help? Post Your Questions Here

Discussion in '2 Stroke' started by Johnnymannen, Mar 24, 2010.

  1. jeanjean Husqvarna
    B Class

    Husqvarna Motorcycle:
    WR 125
    Other Motorcycles:
  2. Berthil Slim Husqvarna
    C Class

    Groningen, The Netherlands
    Husqvarna Motorcycle:
    WR 250 - 2009
    Other Motorcycles:
    Ducati 900 SS
    I also found out that my 2009 wr250 likes running lean at low revs and throttle settings.
    My Keihin PWK 38 AS settings at sea level and at around 0 degrees Celsius (32 degrees Fahrenheit) are PJ40, airscrew 1.25 turns out, DDM needle at #2 (second groove from above) 178 MJ and slide valve #8.
    It runs without virtually any 'blubber' at all loads, speeds and throttle settings and does not bog when opeing the throttle too fast at low engine speeds. Changing the slide valve from #7 to #8 made a big difference in running at about 1/8 throttle in the tight single tracks in first or second gear. On #7 I could not get rid of the slightly rich running ('blubber'), even after installing a smaller pilot jet and a needle with a larger diameter of the cylindrical top part (in this case a DEN).
    It took me quite a while to think about changing the slide - it is fairly expensive and almost anyone uses the stock #7 slide - but it was worth the time and money. Apparently, the slide cutaway dominates the mixture ratio just above the pilot jet's domain and just below the needle diameter's domain. Anyway, I like the crisp running at low engine speeds and the more or less linair power curve with the single taper needle.

    I am an aging rider of mediocre talent riding in sandy and muddy corn stubble and slippery single tracks in the woods in the Netherlands.

    Besides changing from Mikuni TMX to Keihin PWK I installed a 6 speed gearbox from a 1999 wr360. Huge improvement compared to the stock close ratio 5 speeder, low first for the tight stuff and a usable top gear on the road.

    Enjoy 2017,
    justintendo and juicypips like this.
  3. Johan Welander Husqvarna

    Husqvarna Motorcycle:
    Wr 250 2012
    About a year ago i bought a 2012 WR 250 with only 200km on the meter... now it has 46 hours more.

    Last weekend i scored the piston. We were enjoying some freeriding on a big local field, the bike was great as always...
    I had to try its max speed becouse not had the chance to try it out before. A coupple of hard acclelerations from standstill to fifth and some time on fifth gear. Then i turned back and reached third and the bike died without any drama, sounds or resistance. No compression when i tried the kickstarter with my hand.

    I tought i had burned a hole in my piston. We hauled the bike back to my frieds house and i removed the head. Suprised to see the cleanest piston and head in a stroker that i ever witnessed. The next day i brought the bike home and removed the cylinder, pistonrings had trapped themselfs in the heated piston.

    I will try to uppload pictures later tomorrow.

    Is this cause of lean jetting, the manual says to get a 430 main and a 40 pilot on 0deg cels. and at sealevel.

    It was exactly 0 cels and im at 58m above sealevel, running a 420 main and a 42 pilot. Otherwise stock, the bike came with this jetting and a fmf gnarly.

    And yes, im new to jetting a stroker...