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Aprilia forks

Discussion in 'The Garage' started by rodduke, Jan 17, 2013.

  1. rodduke

    rodduke XS400 Member

    Hi guys

    Just wondering what to do with my front end, have seen it posted a couple of times that an Aprilia RS125 front end goes straight into the XS with just the top head bearing needing changing.

    Can you also keep the XS clamps and slip the RS fork tubes in, so clip ons are not required?

    Do you run the RS or XS wheel, are the hubs/spindles compatible also?

    Does anyone have more info on the transplant with maybe some pictures?

  2. elvisrock

    elvisrock XS400 Enthusiast

  3. rodduke

    rodduke XS400 Member

    Thanks Elvis

    Quite a lot of info there and another link off on page 7

  4. Words can not describe how happy I am..on mine the forks are rotten and was looking for USD forks but they were quite expensive for me.These aprilia ones are cheap and look amazing on cadxs' bike..Thanx cadxs!!Will buy you a beer one day!
  5. Charles

    Charles XS400 Addict

    RS125 fork tubes are much larger in diameter than the stock XS400 tubes. You'd need the tubes and triple trees. From there, if you keep the Aprilia wheel, you're good. If you want to use another wheel, you'd need to verify the axle size of the new wheel as to whether it will fit. If not, you can possibly find new bearings with the proper ID and OD. Then you need to worry about the brake rotor spacing. That probably won't be lined up, so you'll need to machine spacers for that. Finally, spacer for the wheel axle.

    If you don't want to use clip ons, you can drill the top tree and mount risers for a traditional handlebar.
  6. Never said it will be easy but I'm ready for the challenge...Or am I?:confused:
  7. Charles

    Charles XS400 Addict

    Depends on how much time and money you have. There's a guy over on Do the Ton that was going to put on some RS125 forks but decided against it. HE might have his setup for sale. Phat..something is his name.

    I'm doing it with GSX-R650 USD forks and CBR929 triples. Just need to get some FZR600 rotors, then I'll start mocking up for spacers.
  8. Sounds complicated to me:laugh: What wheel do you want to use?Have you got some pics?
  9. LuckyEight

    LuckyEight Head-scratcher

    I have RS125 forks (now in gold, new anodized) with aprilia triple trees and stock alloy wheel from XS400 with new bearings (42x20x12), stock bearings are 42x15x13 mm I think. Now I have to solve the problem with axle spacers and speedo drive and order new tyres.
    Last edited: Feb 13, 2013
  10. Charles

    Charles XS400 Addict

    I'm using a 19" wheel from an XS650. It's already drilled for dual discs and I want it to match the stock rear XS400 disc mag I already have. I called All Balls and confirmed they have bearings that will work with the XS650 wheel's bearing housing and the 20mm axle of the GSX-R600.
    No pics. It's not mocked up yet.
  11. Have you got some pictures LuckyEight?
  12. frwinks

    frwinks XS400 Addict

    don't forget about brakes, the 320MM rotors will need spacers behind them as they're not dished as deep as the stock xs rotors.
    Axle spacers, you should only need two spacers on the axle, one for inside the xs wheel and one on the outside. The step on the aprilia (or gixxer) axle will center your wheel in the fork. It'll all fall into place once you have everything in front of you:wink2:
    From there, you can fab up your caliper mounting brackets by hand or give it to the machinist who will cut your rotor spacers (Those you can't cut by hand:D)
    As for the stock speedo? The easiest and cleanest way around that is to run an electronic cycle computer. Put the sending unit on the fork, magnet on the rotor and calibrate it to within a hair/hr.
    The work is worth the effort, you can check out my build thread for more pics:bike:

  13. Did you have to modify the rotor to fit the wheel?
  14. Charles

    Charles XS400 Addict

    The rotor, no. But you do have to space the rotor properly. Of course, when you make spacers, you can also use that as an adapter to run whatever rotor you want. XS400 wheels are 6 bolt, which is why most people run FZR400/600 rotors, but you can use your spacer as an adapter to run 5 bolt rotors.

    Like I said, the easiest way would be to get the wheel that comes with the forks, then you don't have to deal with any of that. It's when you want to use another wheel you have to work a bit to make it fit and everything lines up properly.
  15. ksqrly

    ksqrly XS400 Aficionado

    I want to do this mod so bad!!! Awesome
  16. LuckyEight

    LuckyEight Head-scratcher

    not yet but soon I hope...I am waiting for new neck bearing
    Last edited: Jun 8, 2014
  17. inda_bebe

    inda_bebe XS400 Member

    are these new bearings for the use of stock xs wheels with aprilia forks?

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