need help id on sears bike

[vintage_car]

Guy gave this bike to my dad. It says sears on the tank- I'm not a bike guy. any info would be great.

[R]

From a bit of googling on the web, it looks like these were rebadged Puch 250 machines, mid 1960s.

Its none too clear, but could this be one of the famous "twingle" engines ?
One cylinder immediately behind the other, as a split single, with 2 pistons for a single crankshaft - one does the inlet 2 stroke port, and the other does the exhaust. Quite a good design and performer, apparently, although a complicated way of doing things...

http://allstateguy.tripod.com/

http://www.classicmotorcycles.org.uk/bikemuseum/images/puch/puch_1966_250sgs_250cc_jim_downey.jpg