GSXr forks with ZX10 bottom triple - done!

timsav · Mar 15, 2008

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.

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

JonF · Mar 15, 2008

Excellent post!

MAD-MAX · Mar 15, 2008

very good post and in right time for me!!!:headbang:

GOODRODE · Mar 15, 2008

Excellent JOB!! Very well written rite up.:alcy:

brent6017 · Apr 5, 2008

Nice write up- I just finished my 636 swap to my 750s last night. The forks do seem a bit stiff, but thats what I wanted in the first place.
I was using an 06 636 lower, but found out the stem was too short and had to buy an 03 636 lower. I was wondering, how did you get the steering stem out of the zx10 lower and 636 lower, and then install the 636 stem into the zx10 lower?

timsav · Apr 5, 2008

brent6017 said:
I was wondering, how did you get the steering stem out of the zx10 lower and 636 lower, and then install the 636 stem into the zx10 lower?

Glad you got your the swap done! So the 03/04 and 05/06 636 stems are different.

Swapping over the stems was a case of 'don't try this at home'. I took both lower triples to my local Kawasaki dealer as they have a big hydraulic press and the right bits. It took about 20 mins for them to do and I know that they used heat to expand the alloy first as it was still hot when they brought it out to me.

The stem has a step in it to prevent it being pushed too far through, so it has to be pressed down to remove and up to insert (looking at the yoke as it sits on the bike).

falcn · Apr 11, 2008

Nice post. This was one of the threads that inspired my front end upgrade.

dan_taylor21 · Apr 19, 2008

did you have to use different braided lines once you had swapped over the forks or do the fittings match up to calipers you used from a zx636 to the standard reservoir used already on the z750?

timsav · Apr 20, 2008

I already had replaced the front brake lines with braided ones when I did the original 636 swap. I routed them differently to normal with one line coming down from the master cylinder to a T peice above the fender and then to each caliper. The more common way is to take 2 lines from the master down to the left and right calipers. From reading others posts I don't think you can use the standard z750 or 636 brake lines.

I found a supplier near me who sells hose in any colour and length and screw-on type stainless fittings, so I was able to make up the hose assembly on the bike to fit. If you want to do it the same way I can measure the lengths.

Mega_Milo · Jul 15, 2008

I need 56mm lower triple clamp for ohlins rt forks, what bike / model / year should i look for?

as far as i have found:
07+ gixxer 1000
zx12r
748r 998r 749r 999r
these are 56mm

stunt125 · Jul 16, 2009

triples from Z750 2008 will fit to GSXR K4 forks ? triples from z750 08 and z1000 04 have the same dimensions ?

stunt125 · Aug 5, 2009

Can I use Z750 2004 stem to ZX10 bottom triple ? It will fit ?

timsav · Aug 6, 2009

I really wish I could help you , but I already had a 636 stem on my Z750s, so I got that pressed into the zx10r bottom triple. My z750 stem is still in it's triple.

I do still have the zx10r stem and I can measure it for you and post dimensions and pics, if you want to press your z750 stem out and compare.

stunt125 · Sep 27, 2009

my upradge, gsxr 600 k4 forks, bottom yoke zx10r 2005, top yoke z750 2007, spindle to yokes standard z750 2004 extended by a 9mm, calipers kawasaki 636 2006, spindle to wheel I do spacers to standard z750 2004 spindle, front mudguard suzuki gsxr 1000 2008

timsav · Sep 27, 2009

Congrats on your upgrade! Your bike looks very great.

So the 750 stem fitted into the ZX10 bottom yoke? What to you mean

extended by a 9mm

?

Did you machine spacers to fit around the thinner Z750 spindle to fit the forks?

How do you find the forks? I had to stiffen up the springs a bit, but now they are perfect.

stunt125 · Oct 3, 2009

yes I longered z750 stem because zx10 yoke is roughly than z750 bottom yoke and fitted it to zx10 bottom yoke,

fit around the thinner Z750 spindle I used standard z750 spacers + 2 bushings I do photo

customyota · Oct 3, 2009

I thought of using bushings to fit the stock axle to the forks. But I ended up using a zx6r axle with 24*42*9 bearings doubled up on each side. How did you make those bushings? Also, did the stock axle spacers work as is? Or did you have to modify them? I ended up using modified zx6 spacers on mine.
One more thing, I used the stock Z750 steering stem in the ZX10 lower triple as well, I noticed though that due to the increased thickness of the ZX10 triple, the upper triple was pulled down 8-10 mm and it gave me problems lining up the ignition. Did you machine the bottom of the ZX10 triple, or did you just go with it?

stunt125 · Oct 7, 2009

bushings done turner for 50 zł (10 pounds), I dont machine bottom triple, only stem has been extended I add 9mm, I used standard z750 spacers and all works fine together

Custom1Kbuilder · Jan 12, 2010

lower triple stem questions

So I am attempting to build my own custom KZ1000. I have basically a whole ZX10R, except the engine and components. I ran into kinda the same problem TIMSAV did, with the lower stem being too short. So I can just press another stem in(no prob, since i have a press)? And how will I know how long of one I need, and where about can I get one? Then, what about the bearings? Thanks in advance.

GSXr forks with ZX10 bottom triple - done!

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