Beschreibung:

The urgent need to replace its ageing Commando twin with something more modern for both road and track prompted NVT to commission a new engine design from Cosworth Engineering, applicable to both a production roadster and a race-bike. First shown in 1975, the Challenge water-cooled unitary construction twin borrowed heavily from Cosworth's 3.0-litre DFV V8 Formula 1 engine, yet despite a claimed maximum power output of 115-120bhp, the racer's handful of outings were disappointing, rider Dave Croxford being unable to match his old Commando-powered machine's lap times. With NVT on the point of collapse, the project was shelved in 1976. The Commando-based machine offered here appears to be a test-bed for Cosworth's DOHC four-valves-per-cylinder technology applied to a water-cooled twin-cylinder engine with separate gearbox; as such, it might have been conceived as an update for the Commando engine that would have been cheaper than tooling up for the all-new Challenge. Interestingly, the machine is marked 'P89' to a plate between the instruments, the Challenge project being coded 'P86'. The right-side primary drive and final drive, using a reversed Norton gearbox, are particularly worthy of note. Owned by the vendor for over 30 years, the machine was purchased from Stafford-based motorcycle dealer Cyril Chell, who had bought it at NVT's liquidation sale. The machine has not been used since purchase and its mechanical condition is not known.