Suzuki’s Supermono Engine Design

A second con-rod without a piston

Suzuki engine design
A second connecting rod and rocker arm are used as a balancer on this Suzuki engine design.United States Patent Office

The term "supermono" might have started life to describe a race series for single-cylinder bikes, but in 1993 it became synonymous with the Ducati Supermono that was designed to compete in that class. The 916-derived racer, with styling that made Pierre Terblanche's name famous, was engineered by Massimo Bordi and Claudio Domenicali. All three men would go on to become legends at Ducati, with Domenicali now running the firm, and the Supermono itself was marked out by an ingenious engine that used a dummy cylinder as a balancer, allowing higher revs and more power than its single-cylinder rivals at the time.

Ducati Supermono engine
The Ducati Supermono engine in its frame.Jeff Allen

Now Suzuki appears to be trying the same trick, having filed two patent applications for designs that follow basically the same idea that Ducati used in the 1990s.

The latest Suzuki patent application shows a SOHC engine with a single near-vertical cylinder. On the outside it’s unremarkable apart from a slight bulge at the front of the engine cases. Look inside, though, and it’s clear the bulge hides a second, foreshortened con-rod, attached to the same crank journal as the actual con-rod and, at the other end, to a weighted rocker. It’s exactly the same idea that Ducati used, though its Supermono engine was based on an existing V-twin and retained the forward-facing, horizontal cylinder while using the vertical one as the dummy.

Engine diagram
At the front of the engine a bulge houses a second connecting rod (35) and rocker arm (33).United States Patent Office

The reasoning behind the idea is the same as Ducati’s was more than a quarter-century ago; to provide far better balance than a conventional single can hope for. As a result, the engine can rev much higher—and increased revs means more power.

This is the second recent patent from Suzuki illustrating the same idea. The earlier one, dating back to 2017, showed the same system used on a DOHC single fitted to a motocross bike, which seems an appropriate home for an engine like this.

Supermono design
Will Suzuki ever put this “supermono” design to use on the street or dirt? Only time will tell.United States Patent Office

Will either of Suzuki’s “supermono” patents turn to production reality? Only time will tell, but with original Ducati Supermonos fetching six-figure sums at auction these days—one went for $115,000 at Bonhams Las Vegas in January this year—it’s the only hope that most of us have to ever ride a bike with this engine configuration.