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Help ZXR250 - Specs for fork springs?

Discussion in 'Kawasaki 250cc In-line 4's' started by crshbndct, Mar 15, 2021.

  1. crshbndct

    crshbndct Active Member

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    I am looking to buy some new fork springs to suit my weight, as well as getting my forks rebuilt with slightly heavier oil.

    Does anyone know the specs on the springs?

    All I can find is that the manual says 225mm, but that seems too short?

    Cheers
     
    crshbndct, Mar 15, 2021
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  2. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    225mm is probably right. There's a cylindrical spacer in there that makes up the difference.

    ZXR Fork Spring.JPG
     
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    Frankster, Mar 15, 2021
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  3. crshbndct

    crshbndct Active Member

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    How do I work out what spring rate I need? Or is it best to talk to a suspension guy about it? One of my fork seals blew recently, so I need to get this done ASAP now.
     
    crshbndct, May 14, 2021
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  4. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Spring rate needed depends on your weight. If you change the fronts, the rear shock spring will need to be changed to match if you want consistent operation from front and rear.

    I cannot find any information on the spring rate for the fork springs on the ZXR250, likely that someone will have to buy some and test them (A/C models have different part numbers).

    Racetech have a spring rate calculator, but they don't list the ZXR250. They do have the CBR250RR though, I put that in and for a 65kg rider for street/average skill level it spat out a spring rate of 0.70kg/mm

    https://racetech.com/VehicleSearch

    There are also different types of springs - single rate, dual-rate, and progressive
     
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    Linkin, May 14, 2021
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  5. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    There is an Ohlins manual in the resources section that gives info about setting up suspension and you will probably find more online. Might give you a ballpark to work out how much you have to change things.
     
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    maelstrom, May 14, 2021
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