How to: FZR600 Front End (Fork) Swap

Information related to typical modifications performed on the Seca II.
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FZR600 Front End Swap

FZR Fork and Parts Considerations:

The FZR forks are about 1 1/2" longer than the Seca II forks. If you want to run handlebars or don't want the FZR forks sticking out the top of the upper triple, you can disassemble both sets of forks and use the Seca II uppers with the FZR600 lowers (stanchions). This gives you FZR forks which are the same length and travel as your Seca II forks. If you disassemble the forks, I highly recommend installing new fork seals/dust boots and a new copper crush washer for the damper rod bolt.

The FZR front wheel is 1/2" wider (3" wide) than the Seca II wheel. The recommended tire size by the FZR crowd is a 110/80-17 front tire and not the wider 120/70. You might also consider installing the FZR600 rear wheel as it's 4" wide and allows you to run a 150/60-18 rear tire. This will give you FZR tire sizes to choose from and you can more easily run a matched set. The FZR600 rear wheel is a bolt-on and go modification.

You will want R6/R1 bluedot/golddot calipers from a 1999 to 2003 R6 or R1. After this time, they changed to radial mounted calipers and the newer ones will not work with the FZR forks. The R6/R1 bluedot/golddot calipers will require new brake lines to work as the ones on the R6/R1 are about 4" too short. The R6/R1 calipers have a tendency to get dirty and stick/drag. The common fix is to disassemble them, polish the pistons and install new seals. You should plan on doing this to your calipers before installing them.


Parts List:

You will need the following:
  • 1. FZR600 front forks: Any year from 1990 forward (1989 was an odd year so avoid those)
    2. FZR600 front fender and fender brace
    3. FZR600 front wheel: Again, 1990 forward
    4. FZR600 axle and spacer (the FZR600 axle is smaller diameter and solid whereas the Seca II axle is hollow)
    5. R6 bluedot calipers or R1 golddot calipers: Must be from 1999 to 2003 and look like the ones in the picture below.
    6. Four (4) M10 x 1.25 x 30mm flange-head 10.9 rated bolts (to bolt the calipers to the forks)
    7. One 32" and one 34" long brake line with straight 10mm banjo fittings
    8. One M10x1.25 double banjo bolt for connecting the brake lines to the Seca II master cylinder
I'd highly recommend that you pick up the following maintenance items while you do the work:
  • 1. Fork seals and dust boots for FZR600 or Seca II forks (They're the same)
    2. Copper washers for the damper rod bolts
    3. New brake pads (four of them) for the R6 calipers
    4. Caliper Seal kit (two of them) for the R6 calipers
    5. Front wheel bearing kit with bearings and seals

Modifying the fork:

To build the hybrid fork, disassemble both forks and use the FZR lower and slider bushing and use all other components from your Seca II:
Image

For comparisons sake, here's the differences between the FZR fork and the Seca fork.
The FZR piston is the longer one. Using the Seca II fork piston and internals will give you Seca II fork length and travel without having the forks stick up through the top of the triple):
Image

The FZR600 uses a shorter damper rod than the Seca II:
Image


Calipers and Pads:
You can use calipers from a '99 to '02 R6 or R1. The difference between these being the color of the piston plugs on the side of the caliper; the R6 uses blue plugs and the R1 uses gold plugs. The R6 calipers tend to be cheaper and you can usually find them for under $100 for the pair, in good condition. These calipers use EBC FA252 pads. When buying calipers, compare the pictures and make sure they look like the set below:
Image


The End Result:

Here's my bike with the FZR front end conversion almost done. I'm waiting on the new brake lines. Note that I'm running a 110/80 front tire and bluedot calipers from a 2001 model R6:
Image

The FZR600 fender mounts to the top of the forks instead of the side, like the Seca II. You'll need the FZR fender and the cross brace:
Image

Here's the bluedots mounted up against the FZR rotor:
Image

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