This part is especially for Caddypat. Although your pics gave me lots of ideas for making up the mounts, I couldn't find the correct forged, flat-top u-bolts that I needed to make up the same kind of mounts you have on your Voyager. My Terraplane also has different mounting requirements than your Formula II. But the frame section that I chose to mount to was because of your pics.
I needed to go as high on the bike's frame as possible to get the best rigidity from triangulation. That meant going inside the fairing lower section to grab the frame right behind the radiator and in front of a couple of the exhaust pipes right off the cylinder head! Not much room for clearance, and because of all the heat in this area, I couldn't use one of the polyurethane bushings in this area. So, a hard steel clevis and tab system had to be made up. I bought the clevis from another speed shop, Speedway Motors. They were the only place that had a large, heavy duty clevis with a 3/4" long-threaded shank and at least a 3/8" cross-hole. I had to fabricate the eyebolt-type of tab to hook the clevis to at each end.
This upper end mounting point was built-up from a chunk of aluminum block and a piece of 3/8" steel bar stock, plus a few nuts and bolts and lots of machine work and some welding and grinding.
The two blocks were cut and clamped together and match-drilled, then punch marked to keep correct orientation to each other. One block was tapped for 1/4-20 threads in all six holes while the other block was drilled out to .254" to clear 1/4" bolts (pics 1 and 2). Once the two blocks were bolted together, I located where the hole should be that will go around the frame tube of the bike (pic 3). The bike's frame tube measured at 1.497" exactly, so I bored the hole in the blocks to 1.500" exactly. Sure, that won't let them clamp down at all, but after all boring was done I then cut .040" off the face of each block to give a theoretical .080" clamping fit (pic 4). It worked perfectly! WOW, something went absolutely right this time! No scrapped parts! Now to check for clearance to the radiator and the exhaust pipes.
This project was started right after Thanksgiving, but it's taking so long because most of the early work had to be done outside at the bike and car. It was damn cold and I couldn't spend much tame out there each day laying on cold, snow-covered ground. So, besides this project, I did some more work on the Hondasaki drive project.
The new clamp blocks fit perfectly with about 1/2" clearance behind the radiator and in front of the pipes. I gave the back side a healthy bevel on the corners for better clearance, so it even had room to rotate around the frame tube to give me more choices in how to run my strut tube through the vent slots in the fairing-lower. It was still pretty cramped and I had to make up a special tool just to hold the back block in place while I positioned the front block and started the bolts into the threads.
Now the 3/8" face block and "eye-bolt" had to be made. The steel block was easy to transfer-punch the drill points from the aluminum blocks and drill out. Then a 1/2" hole was also drilled in the center for the eye-bolt. After this block was made up, the aluminum blocks were drilled for clearance for the nut holding this eye-bolt to the steel face block. Several other holes were also drilled to lighten things up a bit on the aluminum clamping blocks. Well, and to add just a bit of bling, too! Hey,....I was in a drilling mood that day and it was too cold to go outside to do any work!
I used a grade-8 fine-thread bolt to weld a 3/8" thick tab to to make up the special eyebolt. I couldn't find any aircraft AN eye-bolts that had all of the specs I needed. My clevises called for a 3/8" thick tab with a 3/8" bolt hole.
OK, now I can hear a lot of "But, you destroyed the grading integrity of that grade-8 bolt by welding it." NOPE! I use a sort of slow-stitch welding technique that Lincoln teaches to keep heat to a minimum. I use high settings on my Mig machine so I can keep my arc duration extremely short but still get deep penetration. After each "spot", I wait almost a minute to allow it to completely cool. I can actually touch the spot right after making it with my bare finger and not get burned! By doing this, there is no heat affected zone around the actual weld bead, or row of overlapping spots. I use this method of welding a lot since I am never in a hurry for my welded projects! Using much lower settings on the machine, it's also the best way to weld sheet metal body panels on a car with absolutely no warpage. BUT, on beads that long, it takes forever!
Anyway, after welding up the eyebolt I ground down the weld to smooth it all out, mostly for appearance. I made up two of these, one for each end of the strut. The final eyebolt, face plate and clamping blocks are shown in pic 5, 6 and 7.