Hi Chainmaker,
There are several manuals about the American Whizzers. The most information about repairing or rebuilding the vintage motors is in the book called "Service Facts". The most information about parts and product information is in the Whizzer Dealer Book.
Owning both of these books is a "must" for vintage collectors, and can easily be found. Another source of information is he currently published Whizzer Newsletter.
Have fun,