NOW that the initial fuss caused by the arrival of the supercharged Kawasaki H2 and its racetrack-only H2R sibling has subdued, it’s time to perhaps take a look back at the origins of forced-induction engines in motorcycles. Back in the ‘30s supercharged racing motorcycles were all the thing, and some of them managed to squeeze 280 km/h out of 500cc engines in land speed record attempts. Matchless / AJS had a supercharged V4, BMW stuck superchargers on their horizontally-opposed twins, and DKW / Auto Union had blown 250 and 350 cc nominally twin-cylinder two-strokes with five bores, five pistons and six connecting rods. Because each of the two pairs of “working” barrels shared a single combustion chamber, with one piston ushering the exhaust fumes out of and the other pumping fresh mixture into the engine, the two cylinder pairs were each considered to make up a split-single rather than a twin-cylinder engine. The fifth cylinder and its piston, without fuel or a spark, was simply a crankshaft-driven pump to pressurise the incoming mixture and help the induction process along – a supercharger, in other words. To understand it a little better and see it in action, click HERE.
Superchargers, that were just the business in GP racing when WW11 started in September 1939, were banned from competition when racing kicked off again in 1946, but in the ‘80s Honda, Kawasaki, Suzuki and Yamaha all brought out turbo bikes that didn’t really sell well and were dropped after a few short years.
Kawasaki really set the motorcycle world alight with their supercharged H2 and it’s unlikely that all of the costs incurred in developing it will result in just one motorcycle from a single manufacturer. Will we see others throwing their hats into the ring? Time will tell, but small supercharged and turbocharged engines are taking over the car market today because, thanks to modern electronic engine management systems, they’re more efficient, use less fuel and are cleaner burning than the much bigger naturally aspirated engines they’ve replaced. We can probably expect to see some bikes with perhaps 400cc supercharged or turbo engines arriving from Europe and Japan over the next few years.
For more information visit Superbike South Africa HERE.
by Gavin Foster