Fzr400 suspension setup

Discussion in 'WERA Vintage' started by gonriding, Mar 7, 2021.

  1. gonriding

    gonriding Member

    I was wondering if anyone could help point me in the right direction with suspension setup on an fzr400...

    I need to know a good starting point for fork length and shock length, the bike is being assembled with a bunch of random parts and a fork swap and I don’t have anything to compare to.
     
  2. shift96

    shift96 Well-Known Member

    Subscribed
     
  3. gonriding

    gonriding Member

    Maybe better to ask in tech? I’ve been scouring the net, but it seems like there are now a bunch of dead ends.
     
  4. evakat

    evakat Well-Known Member

    Have you tried reaching out to Steve at Speedworks?
    He is a 400 guru... and probably knows enough 400 racers to get you pointed in the right direction.
     
  5. Rhino48

    Rhino48 Well-Known Member

    shock length will really depend on which swingarm/shock combo you have. You can't go much over stock with a fox/wp etc. 2.25" spring with the 88 square swinger. Deltabox a bit more, but still there's limitations. something else entirely, you'll probably have to figure out yourself.

    Not many modern cart forks were really long enough for that frame/wheel/radiator getup. You'll probably have one position that just works, and will always be looking for something else.

    Speedworks, however, knows how to overcome all the limitations quite well, as noted above.
     
  6. gonriding

    gonriding Member

    Thank you! It is a deltabox. I was afraid these forks were too short, I have a set of older generation GSXR that have been extended, I’ll just lose the unnecessary but cool looking radial calipers. I think I have clearance on the random eBay radiator, but I guess I won’t know until I grab a handful of brakes.
    I am not familiar with speedworks, how do I find him?
     
  7. Rhino48

    Rhino48 Well-Known Member

  8. gpracer15

    gpracer15 Built to Ride

    SBKBee here on the forum. I think the rear shock length is 300mm and uses a pretty heavy spring weight
     
  9. SpeedWerks Racing

    SpeedWerks Racing Well-Known Member

    Just to get you on the dance floor.
    520mm from the bottom of the steering stop on the frame to the center of the front axle with the forks/chassis unloaded.
    You want all of in the rear [sounds gay]...shock length and shorter dog bones [96 GSXR or similar ], the spring will hit the arm topped out, we machine the arm where it hits for additional ride height. It will just touch unloaded and be fine on track loaded.
    Don't fuck with fork offset much in your swap. GOOD LUCK
     
    FZRCraig and ricracer16 like this.
  10. tgold

    tgold Well-Known Member

    What shock length? I have a Fox Shock and the resources to fab a new clevis if the standard one doesn't have enough adjustment. Or I can shim the upper shock mount.
    I have a 88 FZR chassis with 17" wheels to add to the fun so I'm sure I'll be adjusting the ride height to compensate for that too.

    FZR 400.jpg
     
    Last edited: Apr 15, 2021
    evakat likes this.
  11. SpeedWerks Racing

    SpeedWerks Racing Well-Known Member

    you've changed your shock, top mount, location and type,, standard specs are irrelevant to you,
    give it as much as you can and get the swing arm angle in the ball park. cool self supporting tail/subframe!! some Aprilia hybrid??
     
  12. gonriding

    gonriding Member

    Looks like I’m probably 15mm short on the forks... I was afraid of that. What’s a starting point for swingarm angle?

    thank you so much!!
     
  13. SpeedWerks Racing

    SpeedWerks Racing Well-Known Member

    That's a loaded question,, 11.5-12.5 extended//8.5-9.5 at rest.... as a starting point... there is no magic # for u or Frankenbike,,, do some reading and/or just get it below the pivot for now... And hook a brother up with one of those self-supporting subs... seriously.
     
    ricracer16 likes this.
  14. tgold

    tgold Well-Known Member

    Thanks for the info.
    As for the carbon tail, I layered pink insulation foam from Home depot and hand-shaped it without a pattern. Then I laid up a layer or two of S-glass, some unidirectional carbon fiber in a few spots and the rest is regular carbon weave. I didn't use vacuum bagging and was very conservative with the resin so it's at around 5.5lbs and the finish could be a lot better. I think if I vacuum-bagged it I could get it down to 3 lbs and looking really nice. It's pretty dang strong though. You can lift the back end of the bike with it no problem. I have a crazy amount of hours into it and it would take a lot of convincing for me to make another one that I'd feel was good enough.
     
    evakat likes this.
  15. SpeedWerks Racing

    SpeedWerks Racing Well-Known Member

    We could have someone like,, Ben at Beasley Fiberglass make a plug/mold for ya,,,,,, then you could sell em in glass or carbon, he would give u exclusive rights if you could sell a few,, I know we could... lmk steve@speedwerks.com
     
  16. tgold

    tgold Well-Known Member

    Hmmmmm. I'll have to think about that.

    BTW, I'm already thinking about my next project. You guys wouldn't have a TZR Or NSR roller sitting around would you? I'm thinking about something that I can put KTM 690 motor in.
     
  17. macbook

    macbook Active Member

    Here are my 2bits. Using 520mm front end measurement as a reference. The distance from the bottom of my steering stop to the center of the axle is about 487mm ish, and it worked very well. But my shock has moved a bit, I would let you know my swingarm angle but I'm not sure how to measure it.
     

    Attached Files:

  18. SpeedWerks Racing

    SpeedWerks Racing Well-Known Member

    Take the wheel off, put the axle in and measure center...It'll get you a bit closer..
    For the swinger try an Iphone app like handy level.etc.

    https://apps.apple.com/us/app/ihandy-level/id299852753
     
    Last edited: Apr 23, 2021
  19. SpeedWerks Racing

    SpeedWerks Racing Well-Known Member

    EFC3074D-4C76-4B51-8502-711287ABE41F.jpeg B9C0A8F5-C708-466E-B412-8E38CFE175D6.jpeg
    BTW, I'm already thinking about my next project. You guys wouldn't have a TZR Or NSR roller sitting around would you? I'm thinking about something that I can put KTM 690 motor in.[/QUOTE]

    No 2t stuff lays around anymore,,
    I have a nice custom chromoly trellis we built with a Bimoto style engine mount to take different lumps. Would be perfect for your Ktm. Email or PM me if you’re interested.
     
  20. tgold

    tgold Well-Known Member

    No 2t stuff lays around anymore,,
    I have a nice custom chromoly trellis we built with a Bimoto style engine mount to take different lumps. Would be perfect for your Ktm. Email or PM me if you’re interested.[/QUOTE]
    Very interesting! Sent you an email.
     

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