gsxr 750 rear wheel mod

[Mark Olson]

hey guys,

anybody done the gsxr 750 wheel mod on their fj?
gonna try and help craig get his done before the wcr.
tips and suggestions are welcome.

LA Mike, didn't you do this mod?

[TRoy]

Good info>.. read the messages in this topic and click on the links in 'em.

http://autos.groups.yahoo.com/group/yamahafj/message/102348

I can't say I know exactly what year & model my 5.5" came from but it was marked 93 GSXR600

[Mark Olson]

Troy,

thanks for the info links, it looks to be very easy.

[the fan]

I just did a similar swap on my YZF600, installing a 91 GSXR1100 rear wheel in place of my stock wheel. My inspiration being the link on the Yahoo mods page. Looked pretty straightforward.

Since I was the first (that I know of) to do this, and I tend to ride pretty agressively I took great pains to ensure that I could line up the rotor*, sprocket, and of course the centerline of the wheel exactly the same as stock. I also consulted with Jon Cain while planning this project.

Noting that when the YZF wheel is modified to fit the FJ material is removed from the cush drive to move the sprocket to the centerline of the wheel (3mm?5?), I expected that I was going to have to fashion a spacer between the sprocket and the cush hub. I had to have a spacer made for the rotor as well, so it was no big deal to me.

I also noticed many of the members who did the suzuki mod were saying that they were turning the sprocket backwards to better line up (-1.5mm) with the countershaft. I found this encouraging.


Based on the fact that 3-5mm (not sure on the actual number) is removed from the YZF cush drive when modified to work on the FJ, and that the GSXR wheel required no such modification when used on the FJ, I should have needed to add a 3-5mm spacer to the cush hub when I put the GSXR wheel in my YZF, Right?

Wrong.

When I started measuring the suzuki wheel alongside my YZF wheel I was suprised to find that I did not need to add a spacer to line up the sprockets as I expected, but that I actually had to machine 3mm from the face of the cush drive!

The reason that I post this is that by the above math, The centerline of the GSXR wheel would be offset from the original centerline by 6-8mm when installed on the FJ, unless I am missing something.

Has anyone ever actually measured the conversion to find out? I know that alot of members have done it and that they supposedly ride pretty fast, but math is math. I know that I would be concerned if my wheel was off center by that much.




*The GSXR1100 uses the same diameter rotor as the YZF600 and I wanted to retain my stock rear brake setup so I shimmed the GSXR rotor out to meet the stock YZF caliper.

[Arnie]

The original GSXR wheel swap to the FJ1200 was, AFAIK, mine, done in December of 1998.
I used a 4.5 x 17 inch GSXR wheel from an '87 or '88 bike.  There is a write up and a couple of pics on the Btinternet site.   http://www.fjmods.btinternet.co.uk/Wheels.htm

With my setup and this wheel, I did not need offset sprockets, nor any machining.  I did have to add a 5mm spacer between each side of the wheel assembly and the swingarm.  This lined up the centerline of the wheel and also aligned the chain run.  Yes, I did measure and "do the math" carefully.

Those who have put Suzuki 5.5x17 inch wheels on their bikes may have (prpbably) had different alignment situations than I did.  I would hope they also "did the math", but I cannot vouch for them or their work.

Cheers,
Arnie

[the fan]

Arnie,
I am not trying to call anyone out, I was just very concerned with what I found when I did the conversion on my YZF. If it really is off 6-8mm that could easily be enough to cause serious handling quirks.  I hope that is not the case, but I wonder myself if anyone has checked.

[LA Mike]

Mark,

Yes, very easy just need a GSXR: wheel,brake hanger & caliper and some thin washers. It also might help putting some thin washers under the rear sprocket to get a perfect line with the front sprocket. If you or Craig have any hit me with an email I should be around all weekend.

When you see Craig check to see if wants WCR shirt/hoodie. I'm going check on the design today.


LA Mike

[Mark Olson]

Thanks Mike,

I was just trying to get all the info on the wheel swap before diving in.

when I did my fzr wheel swap it was different than advertised.

I will check with craig about a shirt.

see ya.

[carsick]

 Hey,
  Sorry in advance for using Suzuki parts, this was supposed to be an EASY swap. I have a '93 GSXR750 (so it says) 17 x 5.5" wheel for the back of my '91 FJ. I DID NOT get all the pieces from one bike unfortunately and so seem to be lacking a caliper mounting bracket and perhaps one spacer. I bought a bracket but I think it's too new ('99 maybe), the axle hole is too large and the bracket is too short with the caliper mounted to fit over the rotor. So, anyone know what year (very important!) and model Suzuki I need to pillage for a bracket? The '93 GSXR750's seem to have a funny bracket with a tab that must fit the swingarm instead of using a brake bar, not just 2 ears with holes for the caliper. I have a '96 GSXR750 caliper with the ear for the arm to mount on.
Also, is there a spacer that goes THROUGH the caliper bracket with the axle? I've tried looking at the exploded diagrams on Ron Ayer's website, but they're kinda fuzzy, just like my thinking. I will understand it when the parts are in my hands, but am having trouble picturing what goes in the empty spot! This is the only holdup to installing my spiffy new rear wheel/tire (so far) so I'll be real happy with the correct answer if anyone can help!
Doug

[TRoy]

Hey, is there a spacer that goes THROUGH the caliper bracket with the axle?

Hey Doug the caliper mount is full-floating.. it has a brassy bushing and an inner collar w/seals so that the caliper mount can swivel when the axle is torqued.. which is why its OK to use the long GSXR brake bar hooked on the frame of the bike (like a lot of folks do), instead of hooking it to the swingarm somewhere.

... I chose to modify the GSXR brake bar and mounted it to the lower shock linkage on my 86.




I think you want GSXR1100 or pre-'95 600-750 (read: non-SRAD) caliper mount & bar... not sure exactly what spacer you may need, I ended up using a modified FJ wheel spacer.

[carsick]

 Thanks TRoy,
  I am on the prowl for one! Above and beyond on your reply, the pic really helped.