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

125-200cc carb question

Discussion in '2 Stroke' started by Last Lap, Jul 15, 2010.

  1. Last Lap Husqvarna
    A Class

    Location:
    West Creek, NJ
    The book that came with the 144 is useless. The screw on the left side of the carb is that the idle screw? It seems two be out more than a turn and a half. I started the bike for the first time tonight and I have to keep the choke pulled up slightly to keep it running. I did not want to throttle it up. I just wanted to warm it until warm and the shut it off.

    Thanks,
    Jeff
    Last Lap, Jul 15, 2010
    #1

  2. MattR 2T Forum Clerk

    Location:
    Temperance, MI
    Husqvarna Motorcycle:
    WB165, SM610
    Other Motorcycles:
    Yamaha FZ1
    2T Carb Basics:

    The idle screw on the Mikuni is a silver screw with lock nut (stupid design in my opinion). It's located on left side towards the middle of carb. Loosen the lock nut, then turn the screw inwards to lift the throttle slide (and increasing the idle speed). Outward on the screw, lowers the slide and decreases the idle speed. Tighten the locknut when finished.

    The air screw is located closer to the airbox boot. To lean out the fuel mixture, turn the air screw outwards (adds more air). The richen the fuel fixture, turn the air screw inwards (decreases air). The correct size pilot jet will typically have the air screw about 1.5 to 2 turns out from fully seated.

    Here is a pic of my previous Mikuni TMX. NOTE: I installed a Stealth Racing idle screw (large silver knob) and Zip-Ty air screw (blue color knob). Both cost about $20 each and well worth their money.

    [IMG]
    MattR, Jul 15, 2010
    #2

  3. Last Lap Husqvarna
    A Class

    Location:
    West Creek, NJ
    Thanks. It don't even look like an idle screw.
    Last Lap, Jul 15, 2010
    #3

  4. Last Lap Husqvarna
    A Class

    Location:
    West Creek, NJ
    The only way this bike will run is if the air screw is a quarter out from seated. Any farther out and it bogs and will shutoff.
    Last Lap, Jul 16, 2010
    #4

  5. MattR 2T Forum Clerk

    Location:
    Temperance, MI
    Husqvarna Motorcycle:
    WB165, SM610
    Other Motorcycles:
    Yamaha FZ1
    That would indicate that the carb wants a richer mixture for the pilot circuit. I would swap the pilot jet for one step larger size to let more fuel in (richen the mixture). This should allow you to then set the air screw further outward (such as 1 turn) to balance the air:fuel mixture again. This would provide you some room to fine tune the screw day-to-day.
    MattR, Jul 16, 2010
    #5