If you're suffering from low battery voltage issues on your Bevel Ducati roundcase engine, find a late model alternator rotor that fits in place of the original and use it to replace the stock rotor. Leave the original regulator and stator coil in place, and don't hook up any additional lights or devices to the electrical system.
Malcolm Moore, James de Raeve and Joe Tokarz have all provided extensive information on the OEM regulators used on the Ducati Roundcase engines in the early 1970s. Here is a link to the regulator page for more information.
To start with, Ducati roundcase GT and Sport motors use valve springs like most engines of the 70s and only the 750SS motors are spring-less, with desmodromics doing all the valve opening and closing work. In those days if one wanted to reach the rpms needed for competitive hp, there was little else that would allow a motor to rev and not have valves floating about. Therefore once Guy got into the project he wanted to pull out all the stops and not only do the 750SS desmo head conversion, but also his “” on the Sport heads to bring them into the 21st century.