I owned a ´78 500 Sport Desmo about twenty years ago and I agree with the other poster that it is an incredible ride if it´s properly tweaked and cared for. I got mine as a basket case and rebuilt the entire bike. I used shortened Pantah valves and what was supposed to be an "Imola" cam (sure, and I´m an astronaut...). I wound up using Arias (Mazda) pistons -- which worked reasonably well, but would have used something better if I´d had the resources. I fitted larger flat slide carbs and an aftermarket rectifier/regulator and replaced the stock coils with Accels. I rewired all the electrics and fit an oil cooler. I also replaced the stock Paoli forks with Marzocchi 38mm items and the rear shock with Konis and Prgressive Suspension springs. With Conti replicas it was pure motomusic. It was fast and handled well and **** off the Taglioni True Believers to no end. The motor is exceptionally over engineered and could have taken lots more power. It even has bosses in the cases for a counter rotating balance shaft. Wish I hadn´t sold it.