GSXR 750 front wheel in GS 1000/1100 fork?

[John Kat]

I own two GS 1000 ST's
The first one is almost standard and the second one has been modified to take 1st generation GSXR 750/1100 components (18"wheels, brakes, fork and monoshock suspension).
I like them both but...when I ride the std bike, it takes me at least a quarter of an hour to get used to the way it handles
I'm not sure why there is such a difference but I believe it comes from:
a) the front fork that has no cartridge
b) the crossply tires
Fixing "a" is not difficult with "Gold Valves" from Racetech ( used on my GSXR fork) but fixing "b" is a big issue at least on the front if you want to keep the original fork!
As I had the two bikes side by side, it was easy enough to determine if the GSXR wheel would fit on the GS 1000 fork?
The good news is that the very first GSXR 750/1100 front wheels came with a 15 mm spindle.
It will thus slide right in ...without the disks that stick too far out!
Not to worry, a quick search through the disk suppliers shows that Kawasaki used the same size disks ( 300 mm ) with the SAME pcd but with a smaller offset on their ZZR 600.
Again that should slip in easily
Next the calipers!
Initially, I thought: let's go for the calipers Salty Monk uses in his twinpot conversion but as I didn't have them handy, I decided to try and fit the 4 pot GSXR 750 calipers.
Well believe it or not it can work and the very good news is that the caliper hanger can be manufactured from a single 8 mm thick aluminum plate provided 3 mm spacers are placed between the hub and the disks to get everything in line while keeping the calipers away from the spokes
I need to prototype it to see if it really works but I have already drawn the caliper hanger and it looks OK.
In the end what would we get?
A very light 18" front wheel that can take radial tires, 4 pot calipers on modern disks and worst case the possibility to upgrade to a GSXR front fork.The rear end can also take a GSXR wheel provided you use the GSXR caliper and sprocket carrier.
On the downside, you loose the speedometer pick-up...
Is it worth it? I don't know yet but it's worth a try I believe
Here's the GSXR wheel and caliper I'm talking about:

[GregT]

I've done pretty much the identical swap on a customer GS1000.
ZX1200 discs and the GSXR 4 pot calipers.
The bike is not finished yet & I don't have pics sorry...

BUT - you don't have to lose the speedo drive. I narrowed both ends of the drive assembly carefully in the lathe - put it on a mandrel which is a tap fit to machine it. By reversing the L/H side stepped spacer which goes through the forks you can gain enough room to fit the drive. Make up a spacer for the other side to centralise the wheel and it's done.

Word of warning - some disc attatchment bolts may foul the speedo drive - I cut the outer portion of the hub side back while i had the drive in the lathe.

[John Kat]

Too bad, I thought I would be the first one to discover this
Joke aside, I noticed that the disks you are mentionning come with 1 mm extra offset ( 13.5 vs 12.5) and measure 310 mm vs 300 mm.

http://metalgear.com.au/mgear-brake-disc-front-black-centre-p-6323.html

Are you using the same calipers as mine or the later 4 pot model?
A picture would be appreciated for sure

[GregT]

Not sure what model GSXR calipers they are - the customer supplied them.
I just put the wheels in and set up the caliper mounts etc.
He's got the rolling chassis for finishing.
He comes on here to have a look so...c'mon Ade, pics please.

[John Kat]

I finally got around to get the GSXR 750/1100 6 spoke wheel on a GS 1000/1100 fork
In fact I'm using an 1100 Katana fork as it's slightly longer than the GS 1000 fork.
Instead of milling the speedo drive like GregT did, I preferred to take 1.5 mm away from the inside of the fork.
For the disks, I will be using the 300 mm disks from the K 750 04-06 years.
The offset is 13.5 mm and they clear the fork stanchions with enough room for the calipers to fit.
For the calipers I was tempted to put some AP Racing CP2696-38E0 but given the price and given that I have some 4 pot CP 3369's from the 80's, I will use those.
Here are a few pics:

[GregT]

Do the disc retaining bolts clear the speedo drive and cable ?

The guy I did one for is now a member here so I'll push him for couple of pics.

[John Kat]

Do the disc retaining bolts clear the speedo drive and cable ?

The guy I did one for is now a member here so I'll push him for couple of pics.

I don't have the disks yet but they should as I didn't trim the speedo drive

[kiwimacchi]

Hi guys, my bits are all in boxes, but as Greg says it was a bit of a squeeze! Wheels are '85-87 GSXR 750, discs are 320mm Kawasaki ZXR1200, calipers K3 GSXR750. We tried the K3 discs initially but wouldn't work as no offset, couldnt get calipers to line up. Project is coming along, will post pics soon. GS1000SN(blue) painted ST colour scheme as `I like it better than SN, rearsets off GSXR1100, 4 into 1 with carbon muffler styled along the lines of the Sanctuary bikes. Had already decided to 'black out ' everything before I saw Larry Pearson's awesome GS! Bugger!! Greg pulled engine down, 130,000km, only needs light hone, still stock std bores. Bulletproof old buses.

[John Kat]

Hi guys, my bits are all in boxes, but as Greg says it was a bit of a squeeze! Wheels are '85-87 GSXR 750, discs are 320mm Kawasaki ZXR1200, calipers K3 GSXR750. We tried the K3 discs initially but wouldn't work as no offset, couldnt get calipers to line up. Project is coming along, will post pics soon. GS1000SN(blue) painted ST colour scheme as `I like it better than SN, rearsets off GSXR1100, 4 into 1 with carbon muffler styled along the lines of the Sanctuary bikes. Had already decided to 'black out ' everything before I saw Larry Pearson's awesome GS! Bugger!! Greg pulled engine down, 130,000km, only needs light hone, still stock std bores. Bulletproof old buses.

Welcome to the forum
I will be putting the GSXR 750 wheel on my GS 1000 ST so we will be able to compare our notes.
I have another GS 1000 ST with full GSXR components and it brings the bike in another category alltogether

[kiwimacchi]

Pics of the front end before assembly. Am using 'Mikes XS' copy emulators and progressive springs in std forks. Am having issues with inserting images-sorry!

[John Kat]

Pics of the front end before assembly. Am using 'Mikes XS' copy emulators and progressive springs in std forks. Am having issues with inserting images-sorry!

The easiest way to get the pictures on the forum is to host them on a site like Photobucket and then do a simple copy and paste.
I like the brackets you have made

[kiwimacchi]

Hi again, quite a while since I posted last pictures. I have engine back in bike and things are coming along slowly, what with it being racing season- I have just done several meetings on my Aermacchi with some success after a last minute unexpected rebuild....[/URL][/IMG]
Next, will take a couple of pics with calipers on, but all looking good so far.