mostly got lucky...but i did the research before I jumped on the rear master from the gsxr. I had tried for about 2 months to try and fit the one of my 81 GS1100E...just to big all the way around. I am Also member of the GS Forums, and talked to a few peeps there. When I found the one on ebay, I emailed the kid as to why he wanted so little. He had bought the bike back from the insurance company and was parting out the good stuff....less than 8k miles...so almost new part to my door under 1500 bucks total....I was actually surprised that it fit as well as it did. I used 2 pieces of scrap steel to make the mount brackets, and washers to space it out from inside of frame. When you spin the wheel real good by hand and tap the pedal...the wheel stops.....no slow stopping. This master is designed to stop a 600 pound bike from roughly 160mph...and has 15mm bore....so it should work real well...so far I am impressed....hope to ride the bike in the next month when winter storms go away.
