Suzuki GSX-R750 to CBR600 wheel conversion

First, why would anyone in his right mind want to fit H*nda wheels to his precious Gixxer?
- The need for sticky rubber. These days the only thing you can get for the early GSX-R750's are touring compound tires. When friends tell me their new Michelin Macadam's grip like hell is very, very sad!
- Looks. You may have noticed three spoke wheels are becoming a bit out of fashion. Most GP and SBK teams are switching wheel layouts with more and thinner spokes. And I always think having thicker spokes than forks or frame rails looks a bit off
- Availability = Cost. The CBR600 has been on top of the selling charts on almost every continent for many years. So it won't be very hard to pick some up at a breaker for relatively little money.
- Exclusivity. Huh?... haven't I read the above? Yes I did, but I have never seen a bike with CBR600 wheels other than a -ahem- CBR600. Though a CBR600 front wheel is quite a good match for the VFR750/RC30/NC30 single-sided swingarm many specials use.

The main reason I did the conversion was a follow up after raising the seat unit which made the rear wheel jump out into vision. We all agreed the thin 18" bicycle wheels had to go.

Robby's brother Ruud has a CBR6/9 with a -guess what- VFR750 single sider and still had the old rear wheel laying around so he lent it to me to see if it would fit. Fit?... fit is a huge understatement. What about sliding right in!
I couldn't believe a H*nda wheel would be a straight fit so I started taking exact measurements both from the GSX-R and CBR wheel and was gobsmacked with the results. Not more than a millimeter in it! The chain lined up perfectly and the center of the wheel was within tolerances too.

As you may not know a lot of people run their bike with their wheels terribly out of line simply because the markings on the swingarm are way off, sometimes resulting a 25mm misalignment! The way to check this is by strapping two long bars of material to the rear tire and lining them up to even gaps at the front.

The way I bolted it all together is the following (from the chain- to brakeside); CBR6 spacer / CBR6 sprocket drum / CBR6 wheel / CBR6 spacer / CBR6 caliper bracket / GSX-R spacer all bolted together with the GSX-R axle and chain adjusters.
Because I'm using the CBR's rear brake I cannot use the GSX-R's torque arm any more so a locking plate has to be welded to the swingarm to keep the rear caliper from spinning 'round and 'round. The GSX-R750 can easily take tires up to 180mm wide without getting near to the chain.

The front-end promised to be quite a bit more troublesome reading the specs. The CBR600's discs are 276mm whereas the GSX-R's are 300mm, the front axles are different diameter and the CBR's forks stand closer together compared to the GSX-R's that are 300mm apart.
Ruud also had the complete running gear from a later model CBR600 laying around which means cartridge forks, larger floating front discs and a 0.5" wider rear rim. He wanted to put the new front-end on his own CBR6/9 so a deal was made and I ended up with the 17xMT5.00 rear wheel, rear brake, the complete front-end from his CBR6/9 and a set of tires.

I took the bare GSX-R frame with me when we unbolted the front-end from Ruud's CBR6/9 and shortly after we came to the conclusion my luck hadn't run out yet! The outside diameters of the CBR's steering stem bearings matched the GSX-R's.
The only problem now could be in the length of the steering stem, but that was hard to see because the CBR's steering lockstops fouled the GSX-R's frame. Next day I removed the lockstops from the CBR's lower yoke and the GSX-R's frame with my angle grinder.
I then removed the GSX-R's headrace bearings and fitted the CBR's bearings to discover -this is getting boring- it was again a straight fit.
The only problem I have to solve yet is how to seal the upper bearing so no dirt will be able to get into it.

That's it then... plug 'n play (well nothing a medium sized angle grinder can't solve) CBR600 running gear.

Not much difference looking from this angle...

...but then when you look at it from this side it all becomes clear what's the fuzz about.

Because of the fisheye perspective of a digital camera you can't see the difference in size which is substantial.

The lockstops are removed and it all slides into place.

The specifications of the GSX-R and CBR600 wheels are printed on this page.