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Help MC22 fork springs by race tech

Discussion in 'Honda 250cc In-line 4's' started by sloegin, Nov 16, 2019.

  1. sloegin

    sloegin Active Member

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  2. kiffsta

    kiffsta Administrator Staff Member Contributing Member Dirty Wheel Club

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    Those race tech springs are good for
    Someone who weights about 60-70 kgs


    a lot of mc22 racers are fitting ninja300 oem springs as well
     
  3. sloegin

    sloegin Active Member

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    Thanks for the feedback Kifsta. I’ll look them up.
     
  4. Brizfox

    Brizfox Well-Known Member Premium Member Contributing Member

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    I use the race techs with a mixture of 20 W and 15 W fork oil. Mate I share has just gone from stock to race tech and drop a second off his PB.
     
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  5. sloegin

    sloegin Active Member

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    Are the Ninja EX300R springs this part number?

    44026-0126

    Does anyone know what spring rate they are?

    Thanks.
     
  6. sloegin

    sloegin Active Member

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    According to the racetech site the EX300 springs are 0.65kg/mm

    I checked the price and have ordered a set from Kawasaki UK at £49 for the pair. A lot cheaper than the $300 USD that racetech want for a pair of FRSP S2938.
     
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  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    0.65kg/mm looks a little soft going by what the team tiger guys are saying, but you may be just a little fella below 60Kg

    Interestingly the racetech site now has the CBR250RR listed amongst it's bikes

    https://racetech.com/ProductSearch/12/Honda/CBR250RR/1990-9

    Putting your weight in as 70KG and intermediate track day rider gives a result of 0.74kg/mm

    Try searching:
    FRSP S2938065
    FRSP S2938070
    FRSP S2938075
    etc
    Prices seem to be around $112USD
     
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  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    I thought it was already in the resources section, oops. Well it is now - Racetech Suspension Bible
     
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  9. sloegin

    sloegin Active Member

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    Thanks for that. I couldn’t find them before. When I use the page I get $130 USD each, plus postage to UK, plus the wonderful import duty makes it pricey. I’d rather try the cheap EX300 option for now and see how I get on with it. My RGV has 10% stiffer springs and I’m happy with that so I think for under £50 delivered the kwaka springs are worth the punt for me.
     
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  10. Frankster

    Frankster "Play stupid games, win stupid prizes" Staff Member Premium Member Ride and Events Crew

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  11. crzie

    crzie Member Premium Member

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    Hey sloegin, how’d you go with the 300 springs?
     
  12. sloegin

    sloegin Active Member

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    Hi crzie.
    I haven’t fitted them yet. Been to busy rebuilding my RGV.
    I’ll be fitting them over the next few months.
    I’ll post up whem I’m done.
     
  13. crzie

    crzie Member Premium Member

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    Thanks keen to hear how they go, is it as simple as just replacing the fork springs?
     
  14. sloegin

    sloegin Active Member

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    Finally got around to fitting one tonight.

    Didn’t take long. This is how I did it.

    1. Crack off the 17mm recessed hex socket cap at the top of the fork. Leave in place for now.
    2. Raise the front wheel off the ground so the forks are fully extended.
    3. Undo the 10mm drain bolt at the bottom of the fork and drain the oil (mine was like dirty water and stank, probably 30 years old)
    4. Remove the 17mm recessed hex socket cap from the top of the fork.
    5. Pull out the tubular steel spacer. Note it sits flush with the top.
    6. Pull out the washer which sits on top of the spring between the spring and the spacer tube.
    7. Using a wire hook pull out the spring.
    8. Drop in the Kawasaki EX300 spring.
    9. Drop back in the washer on top of the spring.
    10. Drop back in the tubular steel spacer. It protrudes by approx 170mm. Mark, remove, cut with pipe cutter to sit flush with the top. Don’t use a hacksaw! Drop back in.
    11. Refit and torque the 10mm drain bolt at the bottom of the fork and fill with the correct amount of fresh fork oil. I use a thicker grade to cope with damping a stronger spring and put back the same amount which came out - 400 ml in my case.
    12. Screw in and torque up the 17mm recessed hex socket cap to the top of the fork. You need to apply pressure to compress the spring to allow the thread to mate. Careful not to cross thread it, feel it in.

    Now do the other one :)

    Job done. Budget spring upgrade. No I haven’t ridden it yet.

    If you want to adjust it, get some stiff pvc pipe of the same OD (but thicker wall thickness) as the steel tubular spacer and play with different lengths to alter preload on the spring.

    Hope this helps. Have fun.
     
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  15. jmw76

    jmw76 Well-Known Member Premium Member

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    Keen to know how it actually rides.
     

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