Mounting new engine with new bore x stroke spec
After a 1-year hiatus from factory participation, this new machine was introduced at the opening round of the 1977 season. The engine featured a new bore x stroke spec (54x54 mm changed to 56x50.6 mm). Furthermore, the cylinder pitch was increased (92→115 mm) to allow greater freedom in scavenging port design. The piston valve was changed to a suction type and a power-jet type carburetor adopted to achieve higher revving and increased power output. The aerodynamics of the chassis, including the rider, was re-designed for increased performance. That year Steve Baker mounted the podium in six rounds to end the season ranked 2nd.
- Capacity - 497cc
- Max Power - 100PS