I'm going to redo my '80 SR500. It will be getting spoke wheels, a new exhaust, a cool swingarm, new paint, and I'm sure some other things.
The first thing is the swingarm. I've been thinking about this since talking to the builder of this trick TT500 at Mid-America Speedway in 2015. The swingarm caught my attention right away. YX600 Radian swingarm swaps are very common on the XS650 and 500 Yamaha singles, but are getting very hard to find at a decent price. He explained how many Yamaha steel mono shock swingarms take more work to fit, but are easy to find for a fraction of the cost of a Radian swingarm. He used a XJ600 swingarm on this bike. The pivot needed reworked and he fit a set of multi-position shock mounts from Cheney Engineering.
I got a '89-'90 FZR600 swingarm on ebay for $33 with free shipping, and that was with everything here including the adjusters.
Here it is with the SR500 swingarm. It uses a 16mm pivot bolt, and has a 17mm axle, the same as the SR500. The FZR swingarm is about 7/8" wider at the pivot, and 2" longer.
I started off by cutting a section out of the middle so I could start the mock-up. I also be narrowing the pivot tube.
Here it is for the first test fit. I'm liking it so far. It does interfere with the brake actuator, but so far no other fit issues to work out.
I clamped the lower shocks in place so I could roll it outside and get a better look. I'm not liking the 2" length difference, so decided to shorten it to the same length as the stock SR swingarm.
I first measured from the pivot and marked where the new adjuster slots will need to be, and drilled two holes.
I then cut out the middle with a cut-off wheel, and finished it off with a die grinder.
I then cut off the ends where they needed to be.
I made filler pieces from the cut off sections to fill the old adjuster slots.
Here it is welded in and cleaned up. Once it is all finished I'll measure and mark new wheel alignment lines.
This is the shortened swingarm being test fitted. I like the stock length much better. I also had to cut out the brace behind the pivot for tire clearance, so will need to make a new one closer to the pivot. Next I'll weld the swingarm back together, put shock mounts on it, and fix the brake actuator clearance problem.