Proper Main Sizing

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  • Ranger
    • Jan 2026

    #1

    Proper Main Sizing

    So I have ditched the airbox long ago and have pods, the EMGO or whatever, kinda crappy but I have a budget and need to ride for now. I'll be getting K&N soon enough. What size jet should I go to?

    85 700..
  • Guest

    #2
    What's your stock jetting?

    Comment

    • Steve
      GS Whisperer
      • Jun 2005
      • 35924
      • southwest oHIo

      #3
      You have stock pipes or a header?

      With stock pipes and your "kinda crappy" EMGOs, maybe something 4 to 6 sizes larger than stock.
      With a header, maybe 5 to 8 sizes larger.

      Plan on re-jetting when you get the K&Ns.

      .
      sigpic
      mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
      hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
      #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
      #2 son: 1980 GS1000G
      Family Portrait
      Siblings and Spouses
      Mom's first ride
      Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
      (Click on my username in the upper-left corner for e-mail info.)

      Comment

      • blowerbike
        Forum Guru
        GSResource Superstar
        • Aug 2008
        • 7057
        • Ohio Closer to KY Than Cleveland

        #4
        purchase st.3 jet kit/follow instructions 100%/enjoy the results!
        FYI
        if you are going to purchase a 30 dollar set of filters.... disregard my above comments and continue pulling your hair out as GS CV carbs will never be able to be tuned correctly without a st.3 kit and good filters when the air box is removed.

        Comment

        • Ranger

          #5
          Well I didnt want to put a bunch of money into it until I could get it running and ride it, once that is possible then I planned on that stuff.

          The fire has set my mood back a few days from even looking at my bike though.

          Comment

          • Ranger

            #6
            I'm going with #126 from #122.5 and raising the needle with small washers, any input?

            Comment

            • waterman

              #7
              In general, mains are sized by 2.5 intervals. So if stock is 122.5, next size is 125. It was mentioned to go up 4 to 6 sizes or in your case 132.5 to 137.5 (maybe called 138?). Hope this make sense.

              Comment

              • Ranger

                #8
                Well in that case I'll go with 132.5 but what size for washers to raise the needles would be recommended?

                Comment

                • Steve
                  GS Whisperer
                  • Jun 2005
                  • 35924
                  • southwest oHIo

                  #9
                  The washers that most of us use are found at Radio Shack.

                  They have a bag of assorted washers for about $2, the smallest ones fit perfectly. Stack a few washers to match the thickness of the nylon spacer that normally sits above the clip on the needle, it's usually about 4 washers. Start with half that many, use them in place of the nylon spacer.

                  .
                  sigpic
                  mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                  hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                  #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                  #2 son: 1980 GS1000G
                  Family Portrait
                  Siblings and Spouses
                  Mom's first ride
                  Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                  (Click on my username in the upper-left corner for e-mail info.)

                  Comment

                  • Ranger

                    #10
                    Awesome, will do. I ordered 135s instead hopefully everything will be good.

                    Comment

                    • 7981GS

                      #11
                      Originally posted by Steve
                      The washers that most of us use are found at Radio Shack.

                      They have a bag of assorted washers for about $2, the smallest ones fit perfectly. Stack a few washers to match the thickness of the nylon spacer that normally sits above the clip on the needle, it's usually about 4 washers. Start with half that many, use them in place of the nylon spacer.

                      .
                      Would you happen to have a part # or item # for this bag of washers?
                      I asked at my local one and they all looked at me like I was nuts.
                      They all three said that they do not stock any.

                      Thanks,

                      Daniel

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