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Thread: Bully 3 disc

  1. #1
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    Bully 3 disc

    Wanting to engage the clutch at 3350-3750 stall... on a 3 disc bully...

    Is it better to use stiffer springs and more weight or use weaker springs and less weight?
    Right now it has roller levers, red springs and a bolt in every space outer position...

    It will be used on a smaller displacement motor with low torque and high rpm..

    Thx

  2. #2
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    more weight more clamping force.
    more then one way to skin a cat though , see what the experts have to say .

  3. #3
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    ^ Exactly.

    Weight bolts in outers with springs @ .240" should get you close to the upper end of the rpm engagement that you want.

    I would prefer to add some bolts to the inners as well, and get your spring heights down around .210" or so to be in the meat of the rpm band that you mentioned.


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    Brian Carlson
    Carlson Racing Engines
    Vector Cutz
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  4. #4
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    Thx you sir!!!

  5. #5
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    Not to mention... this set will be on a Jackshaft yz144...
    2.2 primary 26/57...beltdrive
    Then secondary will be clutch 15-17t and rear from 53-60 35 chain...

    The powervalves are removed/plugged...so the start of the engines torque curve 7-8000rpm with HP and TQ peaking at 10-11000 with a peak rpm of 13,000rpm

  6. #6
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    Also the clutch came with roller levers...
    So there are only holes for bolts on the outer of lever...
    And has red springs...set at .275...
    Going by bullers site... that puts it at 3900 stall...
    I would have to get springs out to around .300 to have clutch engage around 3500rpm
    Wondering if I should go to black springs instead?

    The clutch engagement I am looking for is from 3350-3500
    Out of the 3disc bully, with roller levers...

  7. #7
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    I wouldn't back the springs out that far. Technically, you can, but you're completely at the end of adjustment doing it that way.
    You can add washers to the bolts/nuts weight would be my preference over going to the black springs, but you can get there with black springs too. I prefer to use heavier weights and stiffer springs over lighter/softer combos - esp. for higher torque applications.

    I have weight washers in stock -- or just run to a good hardware supply and get machine (thick black) washers.

  8. #8
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    This is where I must ask a question...
    You advise for heavier springs and weights
    For higher torque motors...
    In my application with a yz125... it only puts out a max torque of
    15-16lbs of torque at 10-12,000rpm...

    At 7500rpm where I would like to engage the clutch divided by 2.19 is 3400 clutch engagement...

    At that rpm I am only at 10-12lbs of torque...
    But at 7500rpm the engine is putting out 20hp...

    So I really donít put out a lot of torque???

    Thx

  9. #9
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    If the engine puts out 20 hp at 7500 rpm, that equates to 14.0 lb ft of torque. times 2.19 drive ratio to clutch equals 30.6 lb ft of torque at the clutch.

  10. #10
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    Ok... I see what ya mean... makes sense... thx

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