When Harley-Davidson wanted to replace the Shovelhead engine it had been using in its big V-twin motorcycles since 1966, its answer was the Evolution, an engine with a new design that solved many of the Shovelhead’s problems. When the company wanted a smaller engine to use in its Sportster family, the Evolution 883 was the answer.
The Evolution Engine
In 1984, Harley-Davidson introduced the Evolution engine, a replacement for its Shovelhead engine. Originally offered in a 1,340 cc version, the Evolution engine was manufactured with aluminum cylinders and heads. This construction method had the advantage of being more oil-tight than engines that used different materials for the cylinders and heads, in which the differing expansion rates of the metals when heated could cause leaks. The aluminum Evolution engines were also lighter and more durable than earlier engines. Harley offered the Evolution in five models its first year, including the new Softail.
In 1986, Harley introduced two new versions of the Evolution, an 1,100 cc version and a smaller 883 cc version. In 1988, the 1,100 cc Evolution was replaced by a 1,200 cc version. These smaller versions of the engine featured a different valvetrain layout than the bigger engine used in the larger motorcycles, making the new engines suitable for smaller bikes. The construction of the 1,200 cc Evolution and the 883 were very similar, differing primarily in the size of the bore, and conversion of an 883 engine to a 1,200 cc engine was possible. Such conversions were relatively simple and less expensive than the cost of a new 1,200 cc engine.
The 883 and the Sportster
The 883 debuted in the 1986 Sportster XLH, and it was offered as an option for every Sportster model through 2005. For much of that period, the 883 remained essentially unchanged, requiring only small changes to the engine case when changes were made to the bikes’ transmissions and final drives. In 2004, the mounting of the engine was changed to incorporate vibration-reducing rubber mounts.
The 883 was well suited to the smaller, low-slung Sportsters, and Harley utilized the 883 when it created bikes with a gritty, street racer feel. In 2009, the company introduced the 883 Iron, a modified version of the 883 Low and a member of the “Dark Custom” line. Like the larger Nightster, the 883 Iron featured a satin black finish along with low-rise handlebars and short rear shocks.