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Yz125 Jetting settings

Discussion in 'Fuel' started by Honda241, Nov 12, 2015.

  1. Honda241

    Honda241 PR Member

    Location:
    powell ohio
    2006 yz125 with stock compression running 110 leaded 32:1 with yahamalube 2r. Any suggestions on proper jetting, Im new to two strokes so jetting is not my strong suit.
     
  2. hershey

    hershey PR Elite

    Location:
    Ozone Layer
    Racing Number:
    01
    If you have your manual look there and set it to one size smaller pilot jet, raise the needle clip one position so the needle drops and use the stock main jet. That will be really close.
     
  3. GeorgiePorgie

    GeorgiePorgie PR Founding Father

    Location:
    Ohio the 440
    Racing Number:
    740
    Why are you running 110 ? Not being a jerk, just wondering.

    in my stock 06 I ran 93 pump yamalube 2r 32:1
    Main 430, Needle same spot as hershey said, pilot 47.5

    Now i'm way leaner (400-35) and she still runs rich but with an athena 144 cylinder. I mix 50/50 vp110 and ethanol free 93 sunoco pump.

    what is the bike doing?
     
    Last edited: Nov 22, 2015
  4. Original44

    Original44 PR Addict

    Location:
    Chardon,Oh
    In my sons stock 2015 YZ125, we are running a 410 main, 47.5 pilot and needle in stock position. We are running VP C12 with Yamalube R at 32:1.
     
  5. saplakc

    saplakc PR Addict

    2008 50/50 110 and 93 pump. 430 main. Stock needle second clip and 45 pilot. Air screw depends on temp. When it was below 50 last week I was lean on top with the 430. But it was great all summer.
     
  6. Honda241

    Honda241 PR Member

    Location:
    powell ohio
    Im running 110 because its the cheapest race gas I could find and some say 93 will make the bike ping and blow up. Im going to try 93 with a bit of 110 just because of detonation. It looks like the gas is not burning fully also. Thank you to everyone for your responses!
     
  7. GeorgiePorgie

    GeorgiePorgie PR Founding Father

    Location:
    Ohio the 440
    Racing Number:
    740
    My brothers 2008 yz125 runs 93@32:1. Like clock work. I don't really think there's a need to run race gas in a stock bike. I don't really know though I'm not a chemical engineer.
     
  8. jfalat

    jfalat PR Addict

    Location:
    brimfield ohio
    Racing Number:
    655
    2009 yz125..... stock jetting.... 32:1 at 90 octane... adjust air screw in or out depending on air temp...
     
  9. ahrma479

    ahrma479 PR Member


    I beg to differ:
    Pump fuel is always suspect if you are looking for stability. I did dyno testing when I was at SuperTrapp/Kerker and HMF Racing, using different local fuels and found a huge difference in quality and performance.
    Sunoco was the best pump fuel batch to batch.
    Additives in todays pump fuel make it harder to get a proper AFR than 100% race fuel.
    ALWAYS use race fuel if possible, race fuel is consistent batch to batch, pump fuel is NEVER consistent batch to batch in quality and additives. Always, always test ANY fuel for water.
    I use Kolor Kut:
    http://www.grainger.com/product/KOLOR-KUT-Water-Gauging-Paste-8UNU1
     
    john lilly likes this.
  10. honda907

    honda907 PR Addict

    Location:
    Tyrone, Pennsylvania, United States
    Racing Number:
    04
    I just bought a mint 125, This is the info I needed. Got it for nothing, and I mean nothing as it was under a tarp for 2 years. Kid got in trouble and his dad sold it after the kid lost interest. Title and paid tax on it so it's all legit. Thanks! Yamaha125.jpg
     
  11. jfalat

    jfalat PR Addict

    Location:
    brimfield ohio
    Racing Number:
    655
    nice bike ... looks like brand new...
     
  12. honda907

    honda907 PR Addict

    Location:
    Tyrone, Pennsylvania, United States
    Racing Number:
    04
    420 main, one clip leaner, stock pilot, 2. and 1/8 turns ( 40 degrees yesterday) and the bike goes well. I am surprised at how well it runs for a two stroke. The 250 F's may have to go. He is having a blast, and actually asking to go RACING ( YES I SAID RACING!!) again at AMA events! He hasn't done one of those in years because of the drama at those races. Around here they started a 125 only class! Everyone but A riders allowed . He hasn't done AMA in years because of the drama at those races...........

    He said he likes it better than the 250F, and since he is a ripped 140 lbs, still goes like heck on it.......


    Nice Pic from a local track yesterday. Yes soil was good till it snowed... 2016-03-19 049.JPG
     
    chubakka and MX955 like this.
  13. jfalat

    jfalat PR Addict

    Location:
    brimfield ohio
    Racing Number:
    655
    adding 2 teeth to the rear sprocket v-force reeds and a pipe makes the bike hit so much harder...
     

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