Why Harley-davidson's Switch To V-twins Was Harder Than Just Adding Another Cylinder

Harley-Davidson has been building and trading motorcycles for complete 120 years. But nan first bikes, and really William Harley and Arthur Davidson built them, are acold outcry from really nan Motor Company does things today. The 2 built a mini woody shack successful Milwaukee in 1903, no bigger than a emblematic one-car garage. It was successful that shack that William, Arthur, and Arthur's brother, Walter Davidson, group to activity building motorcycles. But they didn't commencement by slapping a V-Twin into a chassis. No, they started pinch single-cylinder bikes.

In 1909, nan Harley-Davidson Motor Company took a stab astatine its first V-Twin. So that's it, right? The company's first two-cylinder applications were an instant hit, and nan Motor Company was disconnected to nan races? 

Not quite. In fact, Harley-Davidson's first effort astatine a 45-degree copy didn't activity rather right. As it turns out, making nan displacement from single-cylinder bikes to nan V-Twins that would yet specify nan marque and springiness Harley-Davidsons their unique sound wasn't easy.

Let's get 1 point straight: The single-cylinder bikes weren't a flop. After all, nan brand's 35-cubic-inch azygous carried Walter Davidson to triumph successful a 1908 endurance tally and moreover netted an system record. But it didn't return agelong for William Harley to recognize that nan one-pot engines wouldn't support up pinch nan consumer's request for much power. So he concluded that adding different cylinder to nan operation was nan champion people of action. One is good, truthful 2 must beryllium better, right?

Here's nan thing, though: Adding a cylinder presented a caller problem. The new 7-horsepower V-Twin successful nan 1909 5-D Twin used an atmospheric intake-over-exhaust application. In nan previous single-cylinder applications, atmospheric inlet valves operated by utilizing suction created by nan cognition of nan solitary piston. Using a retreating piston to suck a valve unfastened had worked good pinch singles, but not truthful overmuch pinch nan caller 5-D "F-head" twin.

The other measurement (two cylinders astatine 49 cubic inches compared to nan single's 35 cubic inches) reduced that suction's effectiveness and kept nan valves from operating properly. There was a chance Harley-Davidson could person remedied nan problem, but nan squad went a different route. Instead of trying to alteration things up for nan F-head bikes, nan MoCo recalled each 1 of nan 27 it was reported to person built pinch nan early copy and destroyed them.

It didn't return agelong for Harley-Davidson to amended aft nan 5-D's creation flaws. By 1911, nan marque rolled retired an improved Model 7-D twin. Having learned from nan 5-D's finicky valve operation, nan caller 7-D F-head featured pushrod-operated mechanical valves, still successful an inlet-over-exhaust layout. Gone was nan rumor pinch nan atmospheric inlet valves. Finally, Harley had a scalable V-Twin pinch which to summation displacement and support up pinch user demands for accrued powerfulness output. And that's precisely what nan Wisconsinites did.

In nan years that followed, nan motorcycle builder accrued nan F-head V-Twin's displacement to 61 and past 74 cubic inches. But clip stops for nary one, not moreover nan company's then-successful F-head twin. By 1929, Harley-Davidson had its replacement: nan Flathead. Adopting a side-valve layout and a group of characteristic level cylinder heads, nan Flathead powered nan brand's products for complete 4 decades, from 1929 to 1973. 

But nan Flathead was acold from alone. Over nan years, Harley-Davidson would proceed to activity connected improving nan V-Twin connected its measurement to the latest Milwaukee-Eight engines, adding features like overhead-valve construction, physics substance injection, and moreover high-horsepower, liquid-cooled applications with Porsche power. But it each started pinch a troubled modulation from a azygous to a twin.