[Harrison750]

Howdy, I'm stuck on a project and in need of knowledge.

I've been going through a track dedicated 2006 GSX R750 to bring her a little closer to
OEM spec. I'm doing this because I'm new to track riding and while a previous owner
did a great job prepping it for racing or serious track days e.g. smaller rims with racing slicks, lighter chain and a higher gear ratio amongst other things, I don't require the aggressive setup as I'm starting out.

The bike came with two sets of front and rear rims. The rear rim it had when purchased was 16.5" with slicks. As you'll see below it has a spacer welded on to what I believe is the distance collar.

When the axle nut is torqued to spec it fits correctly:

Here is the OEM rim I would like to put on:

And here it is on the bike with the axel nut torqued to the same factory manual spec:

As you can see, there is a considerable amount of space between the spacer and the swingarm - enough so the wheel can move side to side and the brake caliper doesn't fit tight. The OEM rim has all three of its spacers in the correct positions. I'm at a loss. Any help would be gratefully appreciated.

 

[Todd_Sails]

Wow, not sure on your spacer problem.
I remember reading on the WERA forum however that NOBODY uses 16.5" rims anymore? Anyone confirm this?

 

[billv]

OP, you might be missing a part like a collar or the collars that you have are not OEM. Compare what you have with the drawings in the Chassis>Rear Wheel section of the service manual. There one showing an exploded parts diagram and another showing a cutaway cross section. Any chance that the swing arm has been changed?

Todd, I don't follow it but my impression was that 16½" wheels are obsolete. I'm not even sure that the tires are available any more.

 

[Harrison750]

OP, you might be missing a part like a collar or the collars that you have are not OEM. Compare what you have with the drawings in the Chassis>Rear Wheel section of the service manual. There one showing an exploded parts diagram and another showing a cutaway cross section. Any chance that the swing arm has been changed?

Todd, I don't follow it but my impression was that 16½" wheels are obsolete. I'm not even sure that the tires are available any more.

Thank you Bill, I have indeed looked over the exploded section of the service manual and everything appears to be there. Perhaps I just need to take it to a shop to confirm I have or do not have all the components.

 

[rv6john]

Welcome.

There is the possibility that a non-OEM thickness brake carrier is installed? How about a picture of the right side?

 

[Harrison750]

Welcome.

There is the possibility that a non-OEM thickness brake carrier is installed? How about a picture of the right side?

John, thank you for your reply. That's been in the back of my mind, too, as everything else seems to be as it should. I will take some photos soon and upload them.

 

[Chango]

Can you ask the previous owner about it? I don't see any missing spacers either (and I just went and checked the rear wheel on my 06 750 just to be sure), but it's also possible he had the wheel machined down for some reason or something else... For example, when I wanted to stick an 08 600 rear wheel on my 03 SV, I had to get some of the parts machined so they would line up and not destroy each other. I don't see anything specific, but the guy who swapped the parts around should know what he actually did.

 

[Harrison750]

My bike is stored at a friend's as I don't have a space to work at my place, so I don't have pictures of it on the bike, but here are some details of the caliper bracket and caliper:

 

[Harrison750]

Can you ask the previous owner about it? I don't see any missing spacers either (and I just went and checked the rear wheel on my 06 750 just to be sure), but it's also possible he had the wheel machined down for some reason or something else... For example, when I wanted to stick an 08 600 rear wheel on my 03 SV, I had to get some of the parts machined so they would line up and not destroy each other. I don't see anything specific, but the guy who swapped the parts around should know what he actually did.

Hey Chango, thanks for your reply. I believe you're probably right. Unfortunately the guy I bought it from only had it for a year and didn't do any of the conversion himself. I suppose my ignorance about that specific model lead me to believe it was closer to original than it was. Lesson learned.

 

[Harrison750]

Thanks to everyone for your insights. Looking at calipers on Ebay, it's very apparent mine has been machined. Will purchase an original one and hope it solves the issue. Please feel free to continue posting ideas if brilliance strikes.

 

[rv6john]

This is the dimension I was wondering about. It does look like a lot of other dressing has been done to the inside of the carrier.

If you get that measurement, I'll compare it to my K6 750 but it looks like you might have found the answer.

BTW, going back to the 17 is a good idea for track day use. There are so many more reasonably priced tire choices.

 

[rv6john]

I don't need measurement to confirm your brake caliper mount is modified (milled thinner).

This is my K6 750 and the difference is obvious.

 

[Harrison750]

I don't need measurement to confirm your brake caliper mount is modified (milled thinner).

This is my K6 750 and the difference is obvious.

View attachment 295223

Wow, big difference indeed. Thank you for taking a look.
And yes, besides having better tire options I figured it would be a lot easier to sell down the line.
I'll keep my fingers crossed and give an update when the part arrives.