Rocker Ratio

Discussion in 'Engine, Fuel and Exhaust' started by fenmore, Jun 28, 2010.

  1. fenmore

    fenmore New Member

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    What is harley rocker ratio? Is it 1.625 or 1.65 or something else? And also what ratio does the manufactors use on there cams for lift spec?
     
  2. Hoople

    Hoople Account Removed

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    Unless motorcycles are different than the rest of the world, it should be measured right off the cam shaft lobe from the base circle. It should not have a ratio at all.

    Sorry I can't answer part 1 of your question.
     
  3. glider

    glider Veteran Member

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    OEM rockers are 1.625/1
     
  4. fenmore

    fenmore New Member

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    Glider
    In the SE catalog they are using a ratio of 1.65 for there lift spec. Did they change this ratio somewhere along the line, like when they came out with the new 96 motor? So there se257 is 569 lift with 1.65 ratio as the catalog. If stock ratio is only 1.625 then the lift is only 560. Do you know what the other manufactures us for a ratio when they quote there lift specs?
     
  5. glider

    glider Veteran Member

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    I would think that the lift specs would be from the base circle of the cam lobe. You may be best off contacting the manufacturer of the cam you choose to confirm where they are determining the lift specs from before going any further just to be sure.
     
  6. fenmore

    fenmore New Member

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    Thanks
    Glider
     
  7. chad pickens

    chad pickens Member

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    Your talking about 2 different things. The cam has " lobe lift" And the lift that you usually talk about is valve lift which is a variable of rocker ratio.