Home Forums TaG Rotax Max 12.5 vs 8.5

This topic contains 7 replies, has 6 voices, and was last updated by  Bob Baldwin 5 years, 8 months ago.

  • Author
    Posts
  • #4277

    bruce kapanke
    Participant

    Got a motor with a 12.5 on it. Any problems switching it over to a 8.5? Thanks for any help given.

  • #4357

    Mike Maurini
    Participant

    Hi Bruce,

    Carb can easily be changed over to an 8.5. You will have to run a slightly richer main jet but other than that, you will be good to go. Hope this helps!

    Thanks,

    Mike Maurini

  • #4383

    bruce kapanke
    Participant

    Mike,

    Thanks. Gave me the info I needed.

    bruce

  • #6081

    Joe Morales
    Participant

    I’m wondering why? Why the change? Is it to our advantage or disadvantage?

  • #6094

    Bob Baldwin
    Blocked

    mike : Your comment about switching from a 12 to an 8 in the Carb . Being out of Rotax a few years , I was planning on buying a weather station and getting the proper software to determine the best jetting . Should I be holding out on that or will the Proper software have to be re-configured . ?

  • #6238

    Eric Alexander
    Participant

    Bob, most all jetting software has a means of calibrating the software a small percentage for your specific carb/engine combo.  So in the beginning you need to experiment a wee bit and dial the software in.  But then it becomes pretty much enter the weather data and go with few exceptions. 

    None of the software I’m aware of have the venturi as a spec.  Most all do have float weight/idle jet & emulsion tube size/needle type/spark plug/and float arm height.

  • #6278

    Nick Weil
    Participant

    Bob,

    When are you getting back into a kart!?

  • #6281

    Bob Baldwin
    Blocked

    nick : for the Grandson if I can put the $$$ together 

    Slim pickings for Rotax here in the midwest . Nearest about a 7 hour drive one way Michiana

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