I just finished fitting some 04/5 GSX-R 600 forks to my z750s and thought that I would share how to do it. I had 03 636 forks before and I think the GSX-R ones are much better. Although the spring rates are the same (.85 kg/mm) the GSX-R forks are a lot smoother and give a really plush ride. Now when I hit a speed bump it feels like I am riding up it, not into it. The other advantage of GSX-R forks is that they are shorter and don't stick up so far above the top triple - that really annoyed me with the 636 forks.
![Image]()
Parts required:
04/05 GSX-R forks
04/05 GSX-R mudguard (I scored a carbon fibre beauty off eBay)
06/7 ZX10r bottom triple
03/4 636 bottom triple with top nut
z1000 top triple (year depends on if immobiliser is fitted - 03/04 have a smaller hole for ignition fit with no immobiliser 05+ have immobiliser and larger hole). I used a 03 and had to file out to fit the ignition. See: http://www.riderforums.com/showthread.php?t=39043
05 636 wheel, axle, spacers and brakes
Caliper bolts (10 x 60 fine thread)
Spacer 20mm long with 25mm internal diameter and 31 o/d to fill the gap between the thinner 636 stem and the z1000 top triple
2 x Handy shim 25x32x1 mm Suzuki part no: 09181-25139
2 x Handy shim 25x32x.5 mm KTM part no: 47034092000
Loctite 603 or similar
At first I thought of boring out the 636 lower fork clamps from 52mm to 54mm to fit the GSX-R fork diameter, but there is not a lot of material on them and I thought it was best not to risk it and gave the ZX10r bottom triple a go. The ZX10r lower fork clamps are 54mm and fit the GSX-R forks, but the ZX10 stem is too short, so it needs the 636 stem pressed into it instead. This photo shows the ZX10 bottom triple with the 636 stem fitted and the shorter ZX10 stem loose:
![Image]()
When I first tried to fit the lower triple, I thought that the offsets were different and that it did not line up with the z1000 top triple, but it was beacause I was using the zx10 top plastic grease seal which is bigger than the z750's and was pressing on the steering lock and pushing the stem out of alignment, so make sure you use the z750 top seal.
The steering stops on the zx10r triple are different to the z750. The way that I got around this was to tap a thread into the z750 frame behind the lower bearing race and set a bolt there:
![Image]()
Then I tapped into the stops on the zx10 triple and screwed in a bolt each side to allow fine adjustment. It turned out that the gap was too small for the bolt head, so I had to turn the bolts around to get full steering range:
![Image]()
The GSX-R forks are 19 mm shorter than the 636 forks above the axle. I had the 636 forks protruding 25 mm above the top triple, so I set the GSX-R forks at 6 mm above.
![Image]()
![Image]()
The 636 top stem nut fits fine under the handlebars and is just fractionally above the top of the stem when tight:
![Image]()
The 636 axle spacers are 13mm, but the GSX-R forks needed 14.5mm spacers. I could not find any that size, but I did find some very handy shims! By sticking a 1mm and a .5mm shim to the 636 spacer with Loctite I made a couple of 14.5 mm spacers:
![Image]()
The 636 radial calipers fitted over the rotors perfectly, whew...
![Image]()
Next mod will be the swingarm......
Tim
Parts required:
04/05 GSX-R forks
04/05 GSX-R mudguard (I scored a carbon fibre beauty off eBay)
06/7 ZX10r bottom triple
03/4 636 bottom triple with top nut
z1000 top triple (year depends on if immobiliser is fitted - 03/04 have a smaller hole for ignition fit with no immobiliser 05+ have immobiliser and larger hole). I used a 03 and had to file out to fit the ignition. See: http://www.riderforums.com/showthread.php?t=39043
05 636 wheel, axle, spacers and brakes
Caliper bolts (10 x 60 fine thread)
Spacer 20mm long with 25mm internal diameter and 31 o/d to fill the gap between the thinner 636 stem and the z1000 top triple
2 x Handy shim 25x32x1 mm Suzuki part no: 09181-25139
2 x Handy shim 25x32x.5 mm KTM part no: 47034092000
Loctite 603 or similar
At first I thought of boring out the 636 lower fork clamps from 52mm to 54mm to fit the GSX-R fork diameter, but there is not a lot of material on them and I thought it was best not to risk it and gave the ZX10r bottom triple a go. The ZX10r lower fork clamps are 54mm and fit the GSX-R forks, but the ZX10 stem is too short, so it needs the 636 stem pressed into it instead. This photo shows the ZX10 bottom triple with the 636 stem fitted and the shorter ZX10 stem loose:
When I first tried to fit the lower triple, I thought that the offsets were different and that it did not line up with the z1000 top triple, but it was beacause I was using the zx10 top plastic grease seal which is bigger than the z750's and was pressing on the steering lock and pushing the stem out of alignment, so make sure you use the z750 top seal.
The steering stops on the zx10r triple are different to the z750. The way that I got around this was to tap a thread into the z750 frame behind the lower bearing race and set a bolt there:
Then I tapped into the stops on the zx10 triple and screwed in a bolt each side to allow fine adjustment. It turned out that the gap was too small for the bolt head, so I had to turn the bolts around to get full steering range:
The GSX-R forks are 19 mm shorter than the 636 forks above the axle. I had the 636 forks protruding 25 mm above the top triple, so I set the GSX-R forks at 6 mm above.
The 636 top stem nut fits fine under the handlebars and is just fractionally above the top of the stem when tight:
The 636 axle spacers are 13mm, but the GSX-R forks needed 14.5mm spacers. I could not find any that size, but I did find some very handy shims! By sticking a 1mm and a .5mm shim to the 636 spacer with Loctite I made a couple of 14.5 mm spacers:
The 636 radial calipers fitted over the rotors perfectly, whew...
Next mod will be the swingarm......
Tim
