Hi from Australia.
Hey, great forum you guys have here.
I recently started building motorized bicycle myself for the fun of it, and this site provided me with a lot of experiences and engineering ideas.
Currently working on a HS 4 stroke cruiser with cheap single-chain chainbox that came with the kit on ebay.
Finding out that the chain in the chainbox didn't quite line up properly, and chain being quite slack, I'm thinking of adding internal tensioner/chain guide made out of those chopping board plastic materials.
Anyways have fun.