The maintenance manual that I have for my 650 Guzzi, covers this model as well, it looks to be similar to an R65, easy to work on, quite reliable (from an Italian viewpoint !!) but parts may an issue, as not many were brought to the US/North American market .
Guzzi had another 'small' displacement bike, the V50 Monza II (500cc v-twin), saw one in Cycle Trader a month or so back, a '79 model year bike, looked sharp, a dealer in Tennessee had it for about $1700, listing no longer available .