Harley-Davidson Engines

Harley-Davidson’s series of Big Twin engines began production back in the 1910s, and each iteration has served to increase the brand’s visibility and diversity. The motor serves as the heart of any bike, and riders of all kinds value various models based on a range of different characteristics. Some people fall in love with an engine’s look, while some prefer increased efficiency. Others simply want a loud, distinct roar that puts everyone else on alert.

In case you’re wondering what your best fit might be, Susquehanna Valley H-D® has put together a short timeline of the Big Twin’s history that highlights the unique characteristics of each mainstream model.

What Sets Different Harley-Davidson Engines Apart From Each Other?

When any company introduces a new model as part of its production line, it’s meant to improve upon and replace its predecessor. While that’s undoubtedly true in many regards with Harley-Davidson motors, older models still maintain an appeal for many riders for a number of different reasons. The most popular kinds of Big Twin engines include:

• Knucklehead: The Knucklehead, nicknamed for its recognizable fist-like engine valve covers, made history for the H-D brand when it became the company’s first twin to have overhead valves. Produced from 1936–47, this model touted innovations that established it as an influential forerunner for its successors. Its distinctive appearance also inspired enthusiasts to create short-hand terms for future motors.
• Panhead: The Panhead succeeded the Knucklehead, and it became incredibly popular due to its style and overall structure. Its original production run spanned nearly two decades between 1948–65, as it became known for its durability. It featured aluminum cylinder heads for the first time, and it added hydraulic valve lifters, improved oil circulation and crankpin roller bearings. Its popularity in mainstream culture received a significant boost when Panhead motorcycles made appearances in Peter Fonda’s famous 1969 film, “Easy Rider.”
• Shovelhead: The Panhead gave way to another long-running engine model, the Shovelhead, which H-D produced between 1966–84. This model was the company’s response to customers who called for a more powerful motor to compete with other brands, and it mostly delivered on that request. A series of changes — like a shallower combustion chamber and better porting — produced an extra 10 horsepower and a 26 percent sales increase for the company at launch. Due to the engine’s wide availability, accessible transmission and high torque, it’s a popular choice for a lot of restoration projects.
• Evolution: The Evolution model began production in 1984 and ran through the precipice of the new millennium (1999). Many people regard the engine as a game-changer for H-D, which was fighting off bankruptcy during the time of this engine’s inception. It featured significantly reduced weight compared to other models thanks to aluminum heads and cylinders, which also improved its cooling. It remains incredibly popular with a great deal of aftermarket support.
• Twin Cam 88: Before the introduction of the new Milwaukee-Eight in 2017, the Twin Cam 88 became H-D’s primary Big Twin engine from 1999–2016. It was nearly a total redesign from the Evo, utilizing an array of unique components while still adhering to the general aesthetic of previous models. It featured a far more efficient oil pump, while its new combustion chamber promoted better combustion and higher compression. Two chain-powered cam drives significantly reduce the motor’s noise.

If you need help with your motorcycle’s engine in any regard, Susquehanna Valley H-D® will assist you. Contact us today, and we’ll gladly answer your questions, provide advice and address your concerns.