This Is (Probably) The Slowest Harley-Davidson Motorcycle Ever Made

Harley-Davidson is certainly not the first brand that comes to mind when one thinks of screaming fast, performance motorcycles. However, with their large-capacity engines and enormous torque figures, Harley-Davidson motorcycles cannot be called slowpokes either. We have previously discussed how some of the fastest Harleys ever made were capable of reaching top speeds in excess of 140 mph. The company's fastest-accelerating motorcycle — the Harley-Davidson FXDR 114 — had a zero-to-60 mph time of under three seconds. In fact, there even existed a custom-built Harley intended specifically for drag strips. While these are some of the fastest Harley-Davidson motorcycles to ever exist, have you wondered what the slowest model ever from the company was? 

After a bit of digging, we were able to find that the slowest ever motorcycle to sport a Harley-Davidson logo was a model called the Harley-Davidson M50. This motorcycle, manufactured between 1965 and '66, was powered by a tiny 2.5 hp, 50cc, single-cylinder, 2-stroke engine, which propelled it to a top speed of 45 mph. However, the M50's claim as the slowest Harley-Davidson is a bit contentious, given that it wasn't actually manufactured by Harley at all. On the contrary, it was a rebranded motorcycle manufactured by an Italian motorcycle company that Harley had acquired in 1960. 

This revelation prompted us to explore what the slowest ever Harley-Davidson motorcycle — other than the M50 — was. That search led us to the Harley-Davidson Model 125, a motorcycle lineup that Harley introduced in 1948. Despite featuring a higher capacity 125cc engine, it made just 3 hp of power and could reach a claimed top speed of up to 55 mph, making it, quite possibly, the slowest true blue Harley-Davidson ever.

With just 2.5 hp of power on tap, the Harley-Davidson M50 does beat the Model 125 (with 3 hp of power) as the least powerful motorcycle ever to sport a Harley-Davidson logo. That leads us to how this small-capacity motorcycle ended up with the famed logo in the first place. As it turns out, the M50 wasn't developed by Harley, or manufactured in the U.S. at all. 

Instead, the M50 was just a rebadged version of the Aermacchi Zeffiretto, a small-capacity motorcycle manufactured by an Italian company called Aermacchi. In 1960, Harley-Davidson acquired a 50% stake in Aermacchi, a company known for its small-capacity step-through motorcycles. The aim was to capture the attention of young riders to whom small-capacity motorcycles made sense, before upgrading to more powerful models in Harley's lineup. 

As part of this strategy, in 1965, Harley-Davidson launched this motorcycle in the U.S. under the name Harley-Davidson M50. It didn't take long for Harley to realize that the experiment was destined to fail. Only 200 examples of these motorcycles (which also included an upgraded 65cc model called the M65) were built. Harley's association with Aermacchi would result in the birth of several interesting low capacity motorcycles, including the Sprint S350. Harley would eventually sell its stake in Aermacchi to Cagiva in 1978, thereby bringing an end to the company's tryst with Aermacchi.

Now that you have an understanding of the history of how the Aermacchi/Harley-Davidson M50 came to be, you will see how the Model 125 can be called the slowest, least powerful motorcycle ever to be actually made by Harley in the U.S. Unlike the M50 which was a rebranded Italian import. The Model 125's history can be traced back to 1948, when post-war America was in need of fresh, affordable personal mobility solutions. The Model 125's design was heavily influenced by the engineering design of Germany's DKW motorcycles, which were forfeited to the Allies as part of Germany's war reparations.

The first of these motorcycles came out in 1948, and that's the model that featured the 125cc engine that made just 3 hp of power. It was manufactured until 1952, following which Harley-Davidson upgraded the engine on it to a 165cc mill that made 5.5 hp of power. 1953 saw the comeback of the 125cc model again, this time as an economy variant of the 165cc model. Harley called this new model the Harley-Davidson Hummer.

With 5.5 bhp of power on tap, this model was slightly more powerful than the standard 3 hp engine featured on the 'original' Model 125 from Germany. The Hummer often makes it to the list of the slowest motorcycles from Harley, although our research indicates that its predecessor, the Model 125, with half a hp less power, is the true recipient of the title of the slowest Harley-Davidson motorcycle.