I have been racing motorcycles for about 5 years (2012). I race both an F4 (150 cc 4 stroke) and a Pre 82 Class with a Yamaha SR500 1980. I found that changing between bikes at race meetings, meant I never gave either bike my best (whatever that is) as they handled quite differently. The F4 is light and the 500 quite powerful. I then though about combining both these features into one bike.
We have 3 racing clubs here in Christchurch, one is called BEARS (British, European, American Racing) so it would make sense to create a Pre 82 bike that was also BEARS eligible. That meant it had a category in all three clubs.
Twin rear shocks are the norm for Pre82. They are not the best option, expensive and not that adjustable. With a bit of scratching around, I found a few eligible bikes that were mono shock which was my preference. I found a fantastic set of photographs for a YB3 Bimota which I could make my patterns from. PS Only 15 were ever made. A few local phone calls uncovered a source of virtually the identical rear shock as was in the original bike. It is a very long one and a Suzuki Scrambler happens to have the same one. $40 later I had a the shock in my hand. The first bit.