Factory experimentation, DAH!

By 1929 Harley and Davidson were not exactly collecting #1's on the hills or on the tracks like they were in the earlier part of the century. That was possibly the reasoning behind them putting out an OHV 45" race motor called the DAH. This motor was first featured in a factory built hillclimber which there were several versions of
between 1929 and 1932. Some notable features of the bike include dual exhaust heads, trailing-link forks, a single gear transmission, and a Schebler racing carb to feed the alcohol burning engine. Ultimately the experimentation worked and in 1932 Joe Petrali won the National Hillclimb Championship with a double down-tube frame design.



Although I haven't found much info about this motor being used in street or flat track models, I have found a few pics that suggest these were produced at one point or another.


Note: some historians (drunk old bike dudes) credit this successful hillclimbing OHV bike with the popularity the Knucklheads recieved in '36. Although the two engines share nearly zero design traits, some believe that HD had proven it's ability to build OHV engines by first racing one up a 45 degree grade.