In the mid-1990s, Ducati developed the Supermono race bike for the single-cylinder racing class. The Supermono’s 549cc thumper started life as an 888cc 90-degree V-twin before Ducati lopped off the rear cylinder. While the super-single also inherited liquid-cooling, DOHC, and a four-valve desmodromic cylinder head, the Bologna engineers had to account for the missing cylinder.
Luckily, a dummy connecting rod did the trick, balancing the superbike-derived single without the aid of balancing shafts or a crank counterweight. The innovative solution paid off, with the Supermono producing 75 horsepower at 10,000 rpm. Now, the Swedish Buell specialists NCCR are applying the same technology to the Rotax Helicon V2 engine found in the Buell 1125 and EBR 1190.
Of course, the engine’s capacity will be 562cc or 595cc once the team slices off one of the V2 cylinders. However, the firm plans to nix the rear jug for road racing machines while enduro applications will remove the front cylinder. Once the twin becomes a single, the Swedes will install an auxiliary connecting rod and mass balancing module similar to the Ducati Supermono. Despite the new configuration, NCCR will retain the Rotax crankcase and gearbox.
While the Swedish shop won’t start bench testing until winter 2021, the engineers expect stable performance to yield 70 horsepower and a high-performance tune to deliver 90 horsepower. NCCR will also use the super-single to develop a travel-enduro and road racing platform based on its tubular steel trellis frame. The brand is known for its accessories and parts catalog, and it could offer the thumpers, big bore kits (660cc and 700cc), and possibly fully-built machines if all goes according to plan.
Modern street-legal singles from KTM and Husqvarna already achieve 75 horsepower, but they also require a 693-cc capacity to reach those figures. It will be truly impressive if NCCR can squeeze 90 horsepower out of a Rotax Helicon V2 using technology from the mid-1990s.
Thumpers Forever:
