Capacity: 3.49 cc
Bore: 16.4 mm
Stroke: 16.4 mm
Ports: 3 for scavenging, 1 for exhaust
Crankshaft Diameter: 14mm
Plug: Conical 
Reducer : 6.5mm (variable)
Carburetor: Double adjustable

The pre-wrapping means the piston and sleeve are lapped to prevent galling in the early stages of break-in 

and also to facilitate break-ins.