FZR 1000 87-88 fork

[Alf]

I´ve been offered a complete FZR 1000 Génesis 87-88 (41 mm. pre-Exup) complete front fork very cheap, including yokes, mudguard, fork bridge and front discs (BIG 210 mm. ones, in fact my real target to make the conversion)

My idea is using only the fork vases (and the mudguard, the FJ is always cracking due to the speedo cable inducing tension) with my FJ Hagon springs & inner hydraulic units in order to keep the FJ hydraulic regulation

Any experiences?.

[Alf]

No too much experiences, I see.. 

I know that a resprung FZR 1000 fork works wonderfully because I´ve tested it in my friend Bernhard 1TX... and anyway you only have to take a look to Phill Hacker... but really I want to keep the std hydraulic FJ regulation

Another solution I think it would be fitting Randy valves & FJ springs inside the FZR fork vases with the FJ hydraulic unit into the FZR vases...

I will inform

[AustinFJ]

If you are going to use the FZR '87-88 forks, you will need to use the yoke as well.  The fork spacing is narrower by 10mm. The FZR wheel/spacers/speedo drive had the same dimensions as the FJ, so what you end up with is brake  bosses spaced outboard 5mm and 5mm less axle boss on the FZR fork lowers to accept the same wheel/spacers/rotors.   The FZR forks are ~1 inch shorter than the FJ forks as well, so there is a little work to be done there to keep the same ride height and mount the handlebars.
And the rotors are 320mm with 10mm offset.   Used by many bikes so readily available.

[Alf]

Today I´ve received the forks. These need a paint touch, but look straight. The mudguard is in excellent nick and the seller has sent me the axle, spacer, speedo drive, fork bridge and all the OE screws. The rim (even I don´t need it. My bike have one FZR rim fitted) is straight and the even the bearings look ok. The discs are near new

At first glance the first problem that I see to make my conversion is that the fork vases don´t have the screw used to fit the inside hydraulic unit at the rear. Next weekend I will dismount the fork and take detailed measures, The 1 inch difference look like is only at the fork vases being the fork tubes same length. I´m not worried about this difference because now I take the fork tubes protruding 80 mm from the handlebars

Thanks for the info, Austin, but if the spacer/rim/speedo are the same, how the total distance is 10 mm less?

[AustinFJ]

There is 5 mm less material at the inner surface of the axle bosses of the FZR forks.  And the caliper mounts are 5mm further outboard on the FZR forks as well.   So think of it as the wheel, axle, spacers, calipers and rotor position all being the same (calipers also move up the leg to account for larger rotors), but moving the fork legs in 5mm each.   If you put the FZR forks into your FJ triples, slot up the wheel, and put the calipers onto the rotors, you will have a 5mm gap between each side of the axle and fork, and a 5mm gap (and an offset if you haven't bolted up the larger rotors) between the caliper and fork caliper mount bosses.   FJ triples have fork legs at 210mm cl to cl.  FZR triples have fork legs at 200mm cl to cl. 

[Alf]

There is 5 mm less material at the inner surface of the axle bosses of the FZR forks.  And the caliper mounts are 5mm further outboard on the FZR forks as well.   So think of it as the wheel, axle, spacers, calipers and rotor position all being the same (calipers also move up the leg to account for larger rotors), but moving the fork legs in 5mm each.   If you put the FZR forks into your FJ triples, slot up the wheel, and put the calipers onto the rotors, you will have a 5mm gap between each side of the axle and fork, and a 5mm gap (and an offset if you haven't bolted up the larger rotors) between the caliper and fork caliper mount bosses.   FJ triples have fork legs at 210mm cl to cl.  FZR triples have fork legs at 200mm cl to cl. 

Thanks for your help. Yes, I´ve checked that there are less material at the inner surface of the FZR axle bosses... So it is easy to compensate with 2 0,5 mm spacers, but then the mudguard and the fork bridge don´t fit 

Yes, the spacers, callipers, bearings, speedo... are the same, even have the same Yamaha PN. So I think you could use the FZR axle (hollow and lighter) on the FJ forks. Possibly it is 1 cm too short. I will inform

Its clear that I have to get the clamps and fit the complete FZR fork. Do the FJ fork caps fit and could I fit the hydraulic FJ regulation in FZR forks?. I will inform

[Alf]

After searching & fiddling a bit, a pair of conclusions:

- You need the yokes, its sure. The bearings & nuts are the same than those on the FJ (same Yamaha PN)

- I´ve found that inner FZR 41 mm are obsolete and near impossible to find. So a potential problem when searching for spares and clearly a BIG negative point in order to make the conversion.