Letters and Miscellanies

I have a liking for Wisconsin single-cylinder air-cooled
engines. In American Gasoline Engines Since 1872 by C.H.
Wendel, it states that in 1929, Wisconsin started building the
single-cylinder air-cooled engine. Can anyone tell me the first
model number they came out with? Did they have overhead rocker
arms? Or were they valves in block?

I would like to build a collection of Wisconsins and would like
to find the oldest models, but I don’t have an idea what the models
are. Can anyone help me out? Please send information.

Also, can anyone tell me the years they built the Model AB and
BKN? Are these models the older ones? Thank you for any help!

Clayton Brimmer Sr.
17430 Yankee Road
Morley, MI 49336