How I got these pegs to fit ont he rear of my roadstar for my wife.
I hate the look of the factory pegs and wanted something a little cooler and a little longer so my wife could move her foot around if she wanted while riding without having to buy floor boards.
You will need a 3/8" drill bit, 3/8th bolt long enough to go through the mount and an nut to clamp on the other side. Four brass washers per peg and two spring washers each. A cutof wheel and a grinder.
First you drill the holes to 3/8" through the mount then debur the mounts really well. Run the bolt through and make sure it goes in without binding and the holes are straight. Put your peg in the mount at this time as the ears will need to be cut to allow the peg to swivel up and down. Yamaha's design is a pressure spring in the peg itself and works great but its not optimal for this setup.
You will find that followinng the bolt lines is beneficial the peg itself fits perfectly along the flats on both locations so just trimming the corner that it pivots on and leaving half the flat sides on each side is helpful for the stops in the up and down positions. Once the ears are trimmed I ground them smooth with a grinding stone and gave them a slight round radius to the ends and made sure the pegs moved freely from up to down without binding.
Next paint everything black again. I just used rattle can black enamel that I had laying around.
Now that they are black and dry insert your bolt halfway. Put your first washer on then your spring washer then another washer. Next put your peg on and push the bolt thorugh the other side. You will have enough room to get the other two washers in there but you'll need to compress the spring washer that goes in between them. This is the fun part... I used a flat head screw driver in between both washers to compress the one that was already on the mount. Then I pushed the other springs washer on with some needle nose and slowly worked the bolt through to the otherside. Once finished I put a drop of loctite on the bolt nut and tightened them down off the bike. You will need to compress them fairly hard to get them to operate correctly so they don't wobble around they are fairly tight but snugging them up is even better.
I wish I had after pics of the mount but the power went out in my house and my phone and camera were both dead...