From its introduction in 1957 until the late 1960s, Harley-Davidson's 883 Sportster was a badass bike. Bigger and tuned more aggressively than many motorcycles of the day, and much lighter than Harley's 74-series heavyweights, the Sportster, especially the hot CH version, was a bike to be respected.
But toward the end of the '60s, its performance was overtaken by faster, more efficient machines, most with less displacement. The Sportster began to slip from its superbike status, and even adding 1100 and 1200 engines couldn't salvage its powerful personality when other 900s were running quarter-miles under 11 seconds. As other marques introduced ever-larger twins, the Sporty eventually slipped into the position of companion bike, something for riders who wanted a piece of the Harley legend without the price or weight of the bigger twins. There were some Sportster loyalists who preferred it to the big twins, but many of them melted away when Harley introduced Sport versions of its Dyna big twins that mirrored some of the Sportster's attitude but were bigger, stronger, better finished and, thanks to rubber mounts, much smoother.
With the '04 models, Harley changes all that. Although they retain the same basic frame and engine layout, the new Sportsters have been almost totally revised, and are again motorcycles that can be taken seriously on their own merits. There are a number of significant changes-engine improvements, stiffer frames, new brakes, improved finish, etc.-but the most important new feature of the Sportster line is its system of rubber mounts that insulates the rider from the engine's vibration.
The Sportster was one of the very last, and the most popular, of the hard-shaking motorcycles, a fact that diminished the bike. You could admire its unique lines, its distinct position in the world of motorcycles, and other aspects of the bike, and still avoid it like the plague because of its vibration. Vibration, at least on motorcycles, is a bad thing. It makes otherwise good seats uncomfortable, can make it hard to hold a handgrip firmly, and can shake your feet off footrests. Since revving the engine usually increases the magnitude and frequency of vibration, it can be a performance killer because extracting the horsepower that comes at greater rpms is just too unpleasant. And it is tough on the motorcycle itself. Components and their attaching apparatus must be built to withstand the shaking or isolated from it to reduce the wear and tear that shortens their lives.
But for '04, the Sportster blocks vibration with a new frame that incorporates three stabilizer links and rubber engine mounts in place of the solid engine mounts on previous Sportsters. The frame itself is also much stiffer. Even though the engine can no longer serve as a structural member the way it could with a solid mounting system, Harley says the chassis is 26 percent stiffer than previously. It definitely feels that way on the road. On the downside, the beefed-up frame is also significantly heavier, both because of the new engine-mounting hardware and the stronger frame pieces. The added frame mass is the primary reason that the four new Sportsters weigh more-between 54 and 66 pounds, or about 10 to 12 percent-than their '03 counterparts.