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

    Location:
    Netherland
    Husqvarna Motorcycle:
    WR 125
    Other Motorcycles:
    IT175H
    lankydoug likes this.
  2. Berthil Slim Husqvarna
    B Class

    Location:
    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,
    Berthil
    justintendo and juicypips like this.
  3. Johan Welander Husqvarna
    C Class

    Location:
    Finland
    Husqvarna Motorcycle:
    Wr 250 2012
    Hi,
    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...
  4. Johan Welander Husqvarna
    C Class

    Location:
    Finland
    Husqvarna Motorcycle:
    Wr 250 2012
    IMG_4069.JPG IMG_4070.JPG IMG_4159.JPG IMG_4160.JPG
    Heres some pics for u experts!
  5. wait4me Husqvarna
    AA Class

    Location:
    Orange County, CA
    Husqvarna Motorcycle:
    11 WR300
    Other Motorcycles:
    85 YZ490 "Ol Bessy"
  6. Johan Welander Husqvarna
    C Class

    Location:
    Finland
    Husqvarna Motorcycle:
    Wr 250 2012
    Lean enough to cause a that?

    I allso found a rip in my intake boot... ordered a new one.
    Allso a wössner slug... and some jets.

    What needle should i replace the original with? Any good options beside the jd kit?
  7. Oldscool Husqvarna
    A Class

    Location:
    South Australia
    Husqvarna Motorcycle:
    2013 wr125 now 165
    Other Motorcycles:
    2001 rm125
    If the intake boot you're referring too is the one between the carb and the engine, you've found your problem. If it's between the carb and airbox, you've just saved your new top end from wearing prematurely.
    Johan Welander likes this.
  8. Dirtdame Husqvarna
    Pro Class

    Location:
    Escondido, California
    Husqvarna Motorcycle:
    07 TE 450, 11 WR300, 13 WR 125
    Other Motorcycles:
    KDX200,KLX300,Brutale675,Hodaka100
    The JD kit has the best needles in it, a low altitude and high altitude one, as well as a different needle jet. I run the high altitude (richer) one in my 300.
  9. jo360 Husqvarna
    AA Class

    Location:
    perth australia
    Husqvarna Motorcycle:
    1983 exc framed wr430 engine
    Other Motorcycles:
    ktm 520exc
    Was it pinging at all detonation traps the rings causing blow by, burning the oil from the cylinder wall and siezing piston.if your doing lots of high speed increase your oil ratio caster blend is best but clogs pvs.as oldscool said torn boot between carb and cylinder equals lean mixture as does jetting for regular riding then doing constant high revs/high speed esp in cooler climates with greater wind chill.always pays to do a leak down test after seizing and rebuilding.
  10. Johan Welander Husqvarna
    C Class

    Location:
    Finland
    Husqvarna Motorcycle:
    Wr 250 2012
    The bike rips again.
    It was the intake boot that caused it to run lean.
    Got 6h of riding on the new piston.
    Siliconed the boot against the reedvalve frame... its running as strong as before.

    Thanks for the help.
    Oldscool likes this.