I mentioned some time ago that my Dad is rebuilding a Suzuki RE5. The frame is set up to use later Suzuki Katana wheels. Things like this are rarely a direct swap. In this case, aside from basic wheel fitment issues, the Katana is made to use a 520 size chain, while the RE5 uses a 530 chain. Swapping the RE5 to a 520 chain is pretty straight forward, but you need to buy a matching front sprocket and a chain. It was decided that it would be easier to just adapt the RE5 rear sprocket to the Katana hub.
The first thing I did was drill the new bolt holes. In stead of doing the math to figure out where to put the new holes, I just drew up the bolt patterns in Solidworks. From that, it was very easy to measure how far from center in X and Y the new holes had to be. After center finding the hub hole, I drilled all the new holes.
Here you can see the new holes. One new hole overlaps one of the old holes. With a 5 hole pattern(RE5) and a 6 hole pattern(Katana) so close in diameter, you will always have an overlapping hole somewhere in the pattern. On something like this, it doesn't make much difference. Even a modern high power 2L sportbike doesn't have anywhere near enough torque to shear off the bolts.
Then I set about enlarging the hub hole, it needed to be opened up by about 1/4". The easiest way to do this on a manual mill is with a boring bar. I had a whole long explanation of how these things work and how to use them, but it was just boring...
That's really all there is to it. I don't have a pic of the RE5 sprocket on the Katana hub, but it fit like a glove.
