Hi Andrewmc,
If i remember correctly the Dazon was powered by a Suzuki 1100 engine that had been limited/down tuned, A similar sized engine swap would be one of the other Suzuki engines (Car not bike) up to a 1.6 4 cylinder, but at the end of the day it depends on how much additional work you want to do (fabrication wise for things like engine mounts and changes to the chassis) and how much power the chassis / suspension will take in its current form without modification
So what are your fabrication skills like, and what electrical issues are you having?
Rich