Airhead mikuni carb question

Discussion in 'Airheads' started by BarryT, Mar 7, 2011.

  1. BarryT

    BarryT Been here awhile

    Joined:
    Jul 26, 2009
    Oddometer:
    679
    Location:
    Edwards AFB California (Rosamond CA)
    My R75/7 has the rockpoint cycle mikuni kit installed. I was giving it a tune up and realized I have no idea what the needle position is supposed to be. I live at about 2,200 feet and do go down to sea level fairly regularly.


    Thanks
    Barry
    #1
  2. elite-less

    elite-less Been here awhile

    Joined:
    Dec 21, 2009
    Oddometer:
    560
    Location:
    The Puget Sound Convergence Zone
    My r75/5's jet needle came from Rockypoint at the 3rd positions, dead center. However, I'm at sea level and my bike runs best (richer) with the clip at the 4th position. It took a good morning of riding to set my carbs properly... but once dialed in, I haven't touched them in 2 years.

    This website may also be of help:
    http://www.iwt.com.au/mikunicarb.htm
    #2
  3. mykill

    mykill odd

    Joined:
    Feb 6, 2008
    Oddometer:
    1,183
    Location:
    Los Angeles
    Start in the middle and ride a pre-determined route. Then go full rich (bottom clip) and do the same route at the same pace. Better or worse? Try at full lean (top clip) Better or worse? Then work you way back towards the middle where it is best behaved most of the time.
    You should feel the difference coming off of idle through about 3/4 throttle, so don't be in a hurry to go WOT, ride like you like to ride. Hunting, searching and roughness are usually lean. Muddy, flat and unresponsive are usually rich.
    Do yourself a favor and make sure timing, valves, etc are all spot on before you begin this adventure.
    #3
  4. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    +1 mykill! It is so easy to try it all. Why not do it! I might add what advise is right there in the beginning of the Sudco manual. If you can't tell much difference between the richer and leaner settings, stay with the leaner. If he lucks into just the right mix, he might have to raise the needle down at sea level but I doubt it will end up that close. If he was at 4200 feet instead of 2200, you could just about bank on it but . . . .
    #4