The 850 cc MK3 Commando was launched in 1975 with an improved specification – electric starter, isolastic head steady for improved vibration absorption, left side gear change and right side foot brake to comply with United States vehicle regulations, and a rear disc brake. The electric starter did not work as well as planned and could fail to start the engine when cold.
The range of models was reduced to just two machines, the Mk3 Interstate and the Roadster. The specification remained unchanged until October 1977 when the last machines were made, although few Roadsters were made in the end due to the higher cash sales value of the Interstate.
The weight of the Mk3 had risen to 492 lb (223 kg) and combined with the higher gearing made this one of the slowest Commando models with a top speed of around 105 mph (169 km/h). The model was however the most reliable, oil-tight and robust of the Commandos.