Thanks folks,
5Twins. I have the exact same mufflers as in you first picture. I solved the mount for those by swapping the stock muffler mounting plates side for side to gain extra length towards the back. It worked well.
As for the Sportster pipes, I think I have found a solution that is simple, stout and clean.
First I sacked up (had a few beers) and hacked off the useless upsweep on the end of my headpipes. These have always been a pain and usually do nothing but act as a depth gauge for where the baffles begin inside the mufflers.
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Then I offered up the Sporty cans and found I could almost directly bolt them on. Unfortunately, it took just a bit too much force to get them over the footpeg studs. They fouled the shocks and were getting hit by the center stand footpads.
So I had to think of how I could extend the peg studs somehow. I drilled the end of the wheel lug nuts I had installed on them a few years earlier to replace the rusty original acorns. I was going to use the small hole as a drill guide to put a 8mm tapped hole down the center of the peg stud and screw a retainer bolt down the middle of it. That plan went sideways, literally, almost as soon as I began drilling, so I dropped that idea.
Then I had a better idea. The lug nuts themselves are fairly long, too long I often thought, as they were a bit too prominent and squared off for the style of the rest of the fasteners. I thought I could use them as stand-offs to mount the pipes to. I reinstalled the nut and wouldn't you know it, the muffler mounting hole rested against the end of the lug nut perfectly, with the pipe end well away from the shock, and the pipe well away from the center stand. Now I just had to figure out how to get a stud attached.
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The covered end of the nut was only about 3mm thick, so obviously it would not have enough meat to thread a stud into, so I decided to drill a 1/2" clearance hole through the end cap until I hit the 12mm threaded portion. If I had the proper tap and drill for this thread, I think I would have drilled through the end and just finish tapping the entire length of the nut for maximum thread count.
View attachment 179968
I then reversed the nut so that the clearance hole pointed in towards the peg stud and screwed it on until it bottomed out against the peg mount. In this way, I had the OEM threaded end facing outward which gave me the most threads as possible to work with. I used a smaller bolt as a depth gauge and found I had over 1/2" of thread to work with, which will be plenty strong to hold a short 12mmX1.25mm stainless cap screw and washer. This will be a very clean and strong mount.
These are the style of lug nuts I bought at Canadian Tire, although I'm sure they will be available most anywhere.
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Be sure and get ones with the 1.25mm thread pitch. Most are 1.5. Oddly enough, I went searching for more and found none, so they are definitely not as common. Anyhow, this seems to be solved. We'll see if the left side works as well! I'm not sure how well this will work for someone who needs the passenger pegs, obviously I do not.