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Polished Carb

Discussion in 'Motorcycle Tech Talk' started by Tomflhrci98, Feb 23, 2009.

  1. Tomflhrci98

    Tomflhrci98 Active Member

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    Is it good to polish the inside of a carb?
    This carb Im thinking of buying has been "performance upgraded" and the pic shows that it is polished on the inside. How advantages is this?
    Tomflhrci98, Feb 23, 2009
    #1
  3. sarge7

    sarge7 New Member

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    IMO - I wouldn't do it - Has something to do with fuel/air turblence - I'm sure there are others on this forum who could explain it better, but personnel experiance showed me it decreases performance.
    sarge7, Feb 23, 2009
    #2
  4. Tomflhrci98

    Tomflhrci98 Active Member

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    Thanks Sarge and I think you are probably right. I went ahead and bought it off ebay anyway. It comes with a Arlen Ness Big Sucker so I thought what the hell. It may only be polished on the front but I'll find out when I get it.

    I am finally starting to collect parts for my swich over from the MM Fuel injection to carb so this is a good start I hope.
    Tomflhrci98, Feb 23, 2009
    #3
  5. chucktx

    chucktx Moderator Staff Member

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    good luck on finding the parts for the switch!!!! keep us posted on that!
    chucktx, Feb 23, 2009
    #4
  6. Tomflhrci98

    Tomflhrci98 Active Member

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    Yeah I'll put a summary on the Projects area.

    One thing I a looking into gathering info on is ignitions and dual fire coils. I'm thinking about picking up a Dynatech ign. I notice one that is computer programmable and stuff.

    I'm not sure how to spec out the dual fire coils yet.
    Tomflhrci98, Feb 23, 2009
    #5
  7. fujimo

    fujimo New Member

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    switch

    i just swapped my efi for mikuni,,,all parts are in book,,,if you can get dealer to help,,,they do not want to,,,as they are only ones can tune,,,dyno,,, your bike and you realise the cost of that,,, what carb did you buy,,,need an easy kit for swap,,,plus i have big sucker ,,,think it is over rated,,, if you have carb to use,,,rest of cost is in less than 500,,,, pops
    fujimo, Feb 23, 2009
    #6
  8. kenfuzed

    kenfuzed Administrator Staff Member

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    I have polished the opening and venturi of CV carbs for years with very good results in both performance and dyno runs. On the other hand I don't polish the inside of the manifold as I've never seen any improvements.

    That being said, I highly discourage anyone taking a polishing wheel to their carburetor throat. Without being aware of where all of the air bleeds and passages are located you could easily damage or clog something.
    kenfuzed, Feb 23, 2009
    #7
  9. sarge7

    sarge7 New Member

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    Thanks kenfuzed - I forgot to mention that when I posted. There nothing more fustrating than trying to track down something like a plugged port in a carb.
    sarge7, Feb 24, 2009
    #8
  10. ringo912

    ringo912 Active Member

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    I agree with both Sarge and Kenfused. Polishing the intake side of the carb is OK, but not the manifold. You need the rougher surface in the manifold to create turbulance with the incoming air. The more turbulance the better the A/F mixture is atomized. Same thing with the heads. Back in the day it was thought that polishing the ports would improve performance. We now know that is not the case. Ok to polish the exhaust port, but not the intake side. Of course with EFI this is not a concern.
    ringo912, Feb 24, 2009
    #9

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