Well It's been a while but I've finally started making progress again. I outsourced some welding to a shop that took their sweet time and then we got hit by a hurricane but I've finally got my frame back and she's coming along again.
The shop also cut down my new swingarm and made some new inserts so I could keep the original bolt and not have to bore out the holes in the frame.
I decided not to go mono-shock, I love the aesthetic of the dual shocks so the first project was fabbing some mounts for them. I started with a very simple model based on measurements from the old swingarm and some 0.625" thick 6061-T6 aluminum bar stock.
I began by center-punching the holes, started them with a #5 center drill, then ran a 3/8ths bit before finishing with the final 3/4 bit. Then I cut the stock on the drop saw and finished it with the band saw and belt sander. I didn't take any pics of this part because the band saw and belt sander are both terrible and I was focusing on not losing any fingers ;D
Once that was done I did a quick mock up and in exchange for a case of beer my buddy went to town with the tig.
Once they were on and the swingarm cooled off a bit I started the next step, bushing inserts for the shocks. I was originally planning on running OE bushings but unsurprisingly the part is discontinued. One of the perks of a 35 year old bike. Thankfully we had some delrin round stock laying around so I finally got around to learning how to run our lathe and made my own.
Took a couple tries to get right, the first two attempts both wound up around 0.743" and since I need to press fit them in a 0.75" hole that wasn't gonna work. I was getting quite a bit of runout on those tries, 3 thou across less than 2" on the OD so I parted off one bad run and changed the tool insert to a less beat up one and managed to get them down to 0.755" on the last attempt with only about 5 tenths of runout, which is good because I was out of stock by then.
I was a bit worried about the welding distorting my mounts, but they stayed round and the inserts went in with a little hammering and not much fuss.
With that out of the way I had one last project to get done for the rear suspension install. The swingarm is from a 1997 Honda CBR1100XX Blackbird, which I learned (after buying the setup) has linked brakes. 3 Master cylinders and 10 different brake lines allow the front brake lever to operate the rear brake and vice versa. This is done by splitting the calipers into two sections. The outboard pistons of each brake are operated by the usual brake master cylinder. The center piston is operated by the other master, so the front brake lever actuates the rear brake center piston. I'm definitely not going to link the brakes on the CB, so I looked for a solution and found that the center brake piston is shallower than the outer two, and you can connect the center piston to the outer pistons by drilling down into the galley. So we went back to the drill press.
These bolts were a pain to get out, red loctite and everything, it's like they don't want the brakes to come apart or something.
Pulled apart and locked on the press, ready to go.
Again I drilled a pilot hole and then stepped up to a half inch bit since I didn't know how big the passage behind the cylinder was. I may have forgotten to tighten the chuck on the pilot hole.
But the bit was fine so I kept going, hit the passage, and then spent about 10 minutes blowing compressed air into every orifice to clear out the chips before putting her back together.
After that was done I took the parts home and mocked up the new setup. The last bit of welding I have to do with the rear hoop, but I wanted to have the swingarm on first to verify my clearance before I bend the tube and slap it on. For fun I tossed on my new rearsets to check the positioning. Unfortunately I haven't grabbed nuts for them yet so they just kind of fell off, but they looked decently placed before that 8)
Today I'm hunting down the rearset hardware and hopefully I'll have the rear hoop on next week (if we have any tubing laying around that has the correct OD) and I can start pawning everything I own to pay for an m-unit, m-button, and a bunch of connectors to rebuild the harness.