Another historical note on two strokes from the very interesting book, Stealing Speed. It illustrates the success of the tuned pipe, Schnerle scavenged, disk valve two stroke after a lot of attempts with complex, supercharged engines by DKW among others. See the picture below.
Lohring Miller
When Ernst Degner stabbed Walter Kaaden in the back and sold his master's two-stroke secrets to the Japanese, the two-stroke had yet to win a motorcycling world championship. From the first year of grand prix racing in 1949 to the year of Degner's defection in 1961, the four-stroke won 52 world titles, the two-stroke won nothing. Over the next 13 years, as Kaaden's wonder technology percolated through the capacity classes, the four-stroke won 35 world crowns, the two-stroke took 30. Over the following 27 years the two-stroke assumed a position of total domination, winning 104 titles, while the four-stroke won a big fat nothing. Only a change of rules in 2002, permitting 990cc four-strokes to compete against 500cc two-strokes in the elite class, allowed the four-stroke to win again.