Kawasaki KZ650 cafe-racer. Wheels. Part 1.

There is nothing new in using Honda CBX550 wheels, as well as in converting them into spoked wheels. But I suppose, my constant readers waiting for some special features so I’ll try not to disappoint them.

Let’s begin the story of CBX550 wheels’ adapting and converting from the front wheel. Originally Honda CBX550 has 15mm front wheel axle, while 1996 Kawasaki ZX6R which front fork I used in this my project has 20mm front axle. Advantages of thicker axle are obvious, so first issue I had to solve was convert all parts to fit 20mm axle. Wheel hub was simple to manage: it was only question of new bearings with 20mm inner diameter and new spacer. Task of brake boards was a bit harder: some accurate boring had to be done.

As you may see the walls of old axle shaft became too thin, thus reinforcing spacers had to be made.  Bless there are skilled guys in  workshop full of lathe and milling machines not far from my garage, so all I need to do was draw blueprints and handle them along with parts to those guys.

What I really don’t like in CBX550 wheel is brake boards’ asymmetry. As you may see on photo below, right and left boards have quite different configuration because left board was mounted to fork anti dive drive.

After close look on both boards I came to conclusion that I could use another one left brake board to replace right board. So I got spare left brake board and applied to it next list of modifications:

First, brake board has two guide pins for brake caliper. Pins have same diameter, but upper pin is longer and have 10mm thread, while lower is shorter and has 8mm thread.

When left board is place instead of right it stands upside down, so I drilled smaller hole and re-cut it with 10mm thread.   Now I had two holes with 10mm thread and longer pin might be installed in place of short.  One of the longer pins was shortened in lathe machine and provide me lower pin with 10mm thread.

Whole Honda “inboard ventilated disc” system is quite unusual and it has a lot of specific features.  One of them is how brake boards are mounted to the fork. Originally Honda CBX550 right brake board is prevented from rotation around wheel axle by special bolt with 12mm thread and recessed to 10mm pin-like nose. Therefore there is 10mm hole for bolt nose in board, near the upper brake caliper guide pin.

When right board is installed in place of left board slot for bolt nose became useless, as it positioned near the lower pin. With help of specialist skillful with TIG welder I reinforced end of brake board that is opposite to those one with brake slot in it. It was a hard bit of work due to the question of compatibility of different kinds of aluminum. In process resembled some kind of volcanic activity in result of which aluminum became porous, thus perfect surface was hard to achieve.  Once welding and grinding were done I drilled hole absolutely symmetrically positioned to original slot.

In result of these modifications I got two mostly symmetrical brake boards for which I could design symmetrical parts for “boards to fork” mounts.  I also plan to erase all “Inboard ventilated disc” letterings from brake boards to make their look yet a bit more close to look of drum brakes.

The mounts gave me a real headache. It looked like there was no even slight chance to make Honda CBX550 front wheel and Kawasaki ZX6R front fork compatible in easy way. I tried to workout couple of solutions, but they all seemed overcomplicated.  But after some thinking and with some help of one old friend of mine I found solution and begin embody my plan immediately.

First, I cut lower brake calipers’ mount from outer fork tunes and grinded their surface to make a look that there never were any mounts.

Then I cut out two parts from 8mm steel plate, drilled holes and cut thread:

I ordered two sets of machined parts:

And then these parts were welded together:

And that’s how all look assembled together:

To be continued.

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