THE growing popularity of supermoto bikes in Singapore has been boosted by the arrival of the world's most powerful street-legal single-cylinder motorcycle.

The KTM 690 Duke has one of the biggest one-cylinder engines money can buy. That title used to belong to the Suzuki DR800 scrambler and its 800cc unit, but the Japanese bike has been out of production for almost 20 years.

The KTM supermoto, on the other hand, arrived in Singapore earlier this year. But instead of the monster on two wheels that it sounds like, the 690 Duke is surprisingly handsome, with aggressive styling and cool features that combine a slim one-cylinder engine and a distinctive pair of stacked mini-halogen headlamps with WP monoshock suspension and Brembo brakes.

KTM is one of the most technologically innovative motorcycle makers around. The Austrian company is best known for its motocross or dirt, enduro or off-road, and supermoto models. The 690 Duke falls into the last category - a crossover model that is a blend of motocross and road racing bike.

The supermoto combines the advantages of both these bikes - it is easy to ride because it is relatively small and light (kerb weight is 148 kg) and has good low-end power.

Besides a single-cylinder engine's simple design, light weight and durability, another characteristic is its responsiveness.

Unlike other high-rev engines, the single-cylinder's 65 hp power is more usable because its power band is lower (redline is below 9,000 rpm, compared with four-cylinder superbikes that can rev up to 16,000 or 17,000 rpm).

So although you will have to change gears more often, the 690 Duke feels a lot more direct because the power transfer is immediate, with almost instantaneous throttle response. With 65 horses to haul just 148 kg around, that means this KTM has a power-to-weight ratio of 439 hp per tonne - or almost double that of a sports car.

At the same time, the supermoto has a road bike's good handling when it comes to braking and cornering - traits that a motocross or dirt bike does not possess. In other words, the extremely nimble supermoto has fast pick-up and strong brakes - two qualities needed for a satisfying ride.

This is one reason for the growing popularity of supermoto bikes, says KTM importer Dirt Wheel Motor. Another is that the bike is suitable for local riding conditions with congested streets and higher-speed expressways. "They are easy to handle and maintain and the one-cylinder engine provides good acceleration," says Ong Kim Hua, owner of Dirt Wheel Motor. "You can ride them in the city or the circuit, and with its top speed of 180 kmh, it also makes a good touring bike."

Local interest in supermoto bikes has been growing since 2004, with 400cc to 600cc being the more popular models, he says. This year he expects to sell about 100 KTM bikes here, of which about 30 per cent will be supermoto models. As for the 690 Duke, six units have been sold so far and Mr Ong expects more sales. "It's a great all-rounder," he says.

This article was first published in The Business Times on Nov 22, 2008.