Saturday, March 1, 2014

Return of the ST-165

Flathead Rob and I decided to see if we could get the engine running before breaking everything back down again for powdercoating. Word has it the engine was rebuilt just before the bike was disassembled several years ago. I've got to admit, I'm getting pretty attached to this little bike. It sure was cool to hear it running again

I had to ask a friend who really knows Harley Lightweights a couple of questions since we don't have a shop manual on hand yet.  While I was talking to him I asked him what the difference was between the ST and STU 165's offered in 1958. Turns out the answer was pretty intriguing.
In the 50's and 60's, many states had a "junior driver's license" which allowed 14-year-olds to drive motorcycles under 5 Horsepower. These laws were prevalent in the mid-western states. In those days, Go-Karts and MiniBikes were quite popular, and Harley-Davidson tapped the junior market with special versions of the Model 165, Super-10 and Pacer. These had a U in the Model Designator, e.g. STU and BTU.

The U models had a restricted intake system to drop the horsepower to just below 5, making them eligible for junior licensing restrictions. The 125cc Hummer was already eligible, since it only produced 3.5 hp, but apparently many people wanted the increased power and style of the Model 165. 
My friend told me that in the day a lot of the dealers would suggest new buyers remove the restrictor plate if they didn't want it to run like crap. 

1 comment:

Flathead45 said...

Just for the record, the ST165 is officially rated at 5.5 horsepower; the STU165 is rated at 4.7.

Please use that additional 0.7 Hp responsibly, kids.