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

All 2st Zip TY air screw... problems

Discussion in '2 Stroke' started by krieg, Nov 5, 2011.

  1. krieg Husqvarna
    Pro Class

    Location:
    Matthews, NC
    Husqvarna Motorcycle:
    Many in the past
    Other Motorcycles:
    '12 Triumph Scrambler
    I thought long and hard about posting this. But now that I've experienced the same issue on two bikes, I had to tell the story.

    I installed a Zip Ty air screw on my 2011 CR 150 this past Spring (April/May?). After installing the screw, I began to experience erratic idle issues. At the time, I thought this was due to a bunch of other jetting changes I made at the same time. Since then, I was never really able to achieve a stable idle setting on the CR, but I kept the ZT screw in because I thought the problem was related to float level and other jetting issues.

    Yesterday, I installed another ZT air screw in my 2012 CR 125. I immediately noticed difficulty in achieving a stable idle. I futzed with the screw and the idle for about an hour and could never get a stable idle setting. I put the original screw back in at the original setting, adjusted the idle screw to the original setting and all was wonderful again.

    Then I yanked the ZT screw on the 2011 CR and put the OEM screw back in... after a few tweaks, BINGO, stable idle.

    Not sure what is going on here... but the results I've posted are real. After examining the ZT screw and the OEM, it looks like there is a substantial difference in the tip. The ZT screw tapers down to a flat. The OEM screw tapers down to a rounded end.
    krieg, Nov 5, 2011
    #1

  2. Norman Foley Husqvarna
    Pro Class

    Location:
    Trumansburg, NY... The Beautiful, Finger Lakes
    Husqvarna Motorcycle:
    82 250WR 86 250WR 93 WXE350 03 TE610
    Other Motorcycles:
    '85 Fantic 300 '12 HUSABERG TE250
    Nice to know. Too bad it doesn't work, as a quick no tool adjustment, for the air screw on a small bore would seem idea.
    Norman Foley, Nov 5, 2011
    #2

  3. glangston Husqvarna
    Pro Class

    Location:
    Gardnerville, NV and Mammoth Lakes, CA
    Husqvarna Motorcycle:
    2012 Husqvarna TE 310
    Other Motorcycles:
    2012 BETA 350 RS
    You seem to have used sound scientific methods.
    glangston, Nov 5, 2011
    #3

  4. utopia Husqvarna
    AA Class

    Location:
    Jackson, WY
    Husqvarna Motorcycle:
    WR250, WXC125
    You may want to try rounding off the end of the zip-Ty screw to match the oem and see what happens.
    utopia, Nov 5, 2011
    #4

  5. NWRider Husqvarna
    AA Class

    I have the one RB Designs makes and it works great.
    NWRider, Nov 5, 2011
    #5

  6. john01 Husqvarna
    Pro Class

    Location:
    Powhatan VA
    We have the RB one on our 2011 TM SX250 and it works also.
    john01, Nov 5, 2011
    #6

  7. MattR 2T Forum Clerk

    Location:
    Temperance, MI
    Husqvarna Motorcycle:
    WB165, SM610
    Other Motorcycles:
    Yamaha FZ1
    +1 for the RB Designs screw. The RB Designs screw is machined brass (like OEM) and it's profile is be controlled better. It also has a tension spring to preload the screw threads. The aluminum screws tend to be like you described and more conical shape. Also, the aluminum threads are sometimes more sloppy fit. Both can lead to less precise metering of the air passage.

    On my old SM610 with FCR carb, I noticed the same issue on the aftermarket fuel screws. The aluminum ones were junk. The brass ones from Scott or Merge Racing had a nice sharp tip like the OEM screw.
    MattR, Nov 5, 2011
    #7
    jmetteer likes this.

  8. Kevin_TE250 Husqvarna
    Pro Class

    Location:
    Boise Idaho
    Will this wor with the pwk (keihin)
    Kevin_TE250, Nov 5, 2011
    #8

  9. demi Husqvarna
    AA Class

    Location:
    Cheyenne, WYO
    Husqvarna Motorcycle:
    12 WR 300
    Other Motorcycles:
    '14 SH 500, 81 Gilera 125 C1, 17 KTM
    another RB user here... quality stuff, but I think it is only available with carb work?...
    demi, Nov 6, 2011
    #9

  10. MattR 2T Forum Clerk

    Location:
    Temperance, MI
    Husqvarna Motorcycle:
    WB165, SM610
    Other Motorcycles:
    Yamaha FZ1
    MattR, Nov 6, 2011
    #10

  11. 454x Husqvarna
    Pro Class

    Location:
    Dunnigan,Ca.
    Husqvarna Motorcycle:
    2012 CR165 w/36mm lectron.
    Other Motorcycles:
    2014 BETA 300RR w/36mm lectron.
    454x, Nov 6, 2011
    #11

  12. 454x Husqvarna
    Pro Class

    Location:
    Dunnigan,Ca.
    Husqvarna Motorcycle:
    2012 CR165 w/36mm lectron.
    Other Motorcycles:
    2014 BETA 300RR w/36mm lectron.
    He makes a screw for the Mikuni?
    454x, Nov 6, 2011
    #12

  13. demi Husqvarna
    AA Class

    Location:
    Cheyenne, WYO
    Husqvarna Motorcycle:
    12 WR 300
    Other Motorcycles:
    '14 SH 500, 81 Gilera 125 C1, 17 KTM
    ^^ yes, nice piece too. Only available with carb work of some sort however...
    demi, Nov 7, 2011
    #13