History

Until the late 1960s motorcycles came in three basic formats:

• Working bikes: Generally below 250 cc (15.3 cu in) displacement and low-powered for commuting and utility travelling.
• General bikes: Generally below 500 cc (30.5 cu in) / 650 cc (39.7 cu in) for use as a working bike, but with a higher power output so it could also be used for fun on the weekends.
• Touring bikes: Anything above working/general bike sizes and built mainly for touring.

The first company to crack this mold was arguably Vincent Motorcycles. Designed as a gentleman's touring bike, their model's speed was astounding for days when motorways and freeways didn't exist. However, its handling was basic, and its shortcomings became clear when faced by a motorway - girder forks. By the 1960s bikes were developed which could be both daily commuter as well as weekend racer, including the BSA Rocket 3/Triumph Trident.

However it was the introduction in 1969 of the Honda CB750K that initiated the era of the modern sport bike ^[1]. The CB750 was the first bike to have an overhead-cam in-line 4 engine and a front disc brake; the bike was acclaimed as "the most sophisticated production bike ever" by Cycle Magazine ^[2].

The Honda CB750 was followed in by the 1971 Kawasaki Z1, with its 900 cc (54.9 cu in) DOHC engine, and this firmly established the modern sport bike (or superbike). These bikes sold so well that by the end of that decade the Japanese manufacturers were all building competing machines with DOHC inline-4 engine configuration. The resulting "bike war" among the Japanese manufacturers and required investment in modern engine manufacturing contributed to the demise of the flagging British motorcycle industry.