HARLEY-DAVIDSON BIG TWINS ENGINE TIMELINE

1903 is undoubtedly a memorable year, it is the year Harley-Davidson was born, from then on to lead the freedom-loving riders of some would say the best motorcycle on the road. The first Harley
Davidson bike posted a single cylinder engine that delivered 3.9 HP. However, the Harley Brothers and Arthur Davidson soon determined that more power was needed and introduced Harley’s first V-twin in 1909 that was the beginning of Harley Davidson’s reliance on V-twin engines. The single cylinder engine that was used at that time, the F-Head had a displacement of about 800 cc and were produced from 1914 through 1929.

In 1936, Harley Davidson made a big change in their engine design, with the knucklehead engine in the form of overhead valves came out. The position of the valve is changed from the side design of the Flathead to the top. This design added a more efficient engine oil lubrication system. These technologies and features have been used to this day. The knucklehead got its name from its rocker boxes that looked like knuckles on a human fist. Both 61 cubic inch and 74 cubic inch models of this Big Twin engine were produced by Harley-Davidson. The Knucklehead was made through 1947.

The famous Harley-Davidson Panhead engine was in service for 17 years, from 1948 to 1965. This Big Twin engine gets its name from the peculiar cake pan-like appearance of the rocker covers. The Panhead engine was equipped with aluminum heads and hydraulic valve lifters. In 1965 the Electra Glide model introduced an electric starter on a Harley Davidson motorcycle. The Panhead Engine pushed the power level up to 70 HP, which was an improvement, but riders demanded more.

Produced from 1966 until 1984, the Harley Davidson Shovelhead engine was available and 74 cubic inch and 80 cubic inch models. The Shovelhead is the third version of Harleys overhead valve V-twin motor. The cylinder heads are aluminum, the cylinders are cast-iron, single camshaft with four cams, and two valves per cylinder. This design helped the engine produce more power and higher performance to make up for the increase in weight of the new engine. The Shovelhead earned its name due to the appearance of the rocker covers. The slightly rounded Shovelhead rocker box covers are like small shovels, with the pushrod tubes serving as the handles.

From 1984 to 1999 Harley Davidson produced the Evolution engine. Compared with Shovelhead, the biggest difference in appearance of Evolution are the cylinder heads, upper and cylinder blocks are all made of aluminum alloy, which improved the weight and heat dissipation effect. The 80 cubic inch motor was not only more powerful, but it ran cooler and smoother than the Shovelhead.

From 1999 to 2016 Harley Davidson produced the ever so popular Twin Cam engine. In 1998 the introduced the 88 in.³ twin cam engine for the 1999 model year and continued production of different models until 2016. The twin cam 88 pushed out a maximum of 62 HP from the factory. The 96 cubic inch had a slight boost up to 66 HP. Following that, the 103-inch provided up to 75 HP, and the final engine in the twin cam era, the 110 inch, pushed the ponies to 90 HP. The Revolution engine arrived on the scene next. They were used on the Night Rod, Street Rod, V-rod, and the Screaming Eagle V-rod. That engine produced a whopping 125 hp from the factory.

Next, in 2017 Harley Davidson treated the world to the Milwaukee-Eight engines. Milwaukee in honor of its birthplace, and the “eight” refers to the engine’s eight valves. The eight valves help to boost performance levels, with the Milwaukee-Eight 131 model boasting up to 115 HP from the factory. The new engine platform provides faster throttle response, more torque, better sound, improved fuel economy and a smoother ride.