Sunday, October 11, 2015

Just a little sprocketing

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. 




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