Moving on to the front forks. I get a lot of sag when I sit on the bike. The spec on the springs is 19.1". Mine measure 18.875". None of my manuals state a service limit for the springs.
I read a few articles about the Minton Mods recommended for XS650s, including the
original from Motorcyclist magazine in 1981 and decided to do some of the fork mods.
Minton suggests drilling two more 1/4" holes in the dampers for a total of 4. My dampers already had 4 holes in them so I drilled them out to 1/4". They were just under 1/4" to begin with.
Then I cleaned up the holes with a file.
Minton says to drill the top hole all the way through to the other side for a total of 2 holes. My dampers already had 2 holes, albeit side by side, so I opened them up a bit and then polished the dampers by wet sanding with 400 grit paper. To finish I blew them out with the compressor to get all the gunk out.
He suggests changing the seals as well but the dimensions of the ones he lists may be too big for my 33mm forks so I ordered stock seals from Yamaha. They need to come from Japan but are still available.
I will fill the forks to 6" below the top (when compressed) and stick with the stock 20W fork oil for now.
The last outstanding issue is the springs themselves. Although I realize new Progressive Suspension #11-1109 are the best solution for my weight, I want to try a spacer before ordering new springs.
I have some Honda dampers lying around and thought of using the damper springs as spacers. They measure 22mm wide (the Yamaha fork springs are 23mm) and .77" long.
My fork springs are ~.2" short. The suggested Progressive springs are .65" longer than mine are supposed to be at 19.1". So maybe a spring spacer of this length would be OK. Unless someone here says why I shouldn't try it, I think I will. I can just barely squeeze them under the fork caps and still get the caps on.
I have to wait another week or so for the seals and then I can get them back together. In the meantime I'm open to suggestions.