Series 2 Back fire

Glad that helped. It sounds like your carb needs either clean innit or setting up or both. Once the engine can run on tickover it's a case of fiddling with the air mixture screw and the throttle stop on the carb to get the smoothest tickover. Try screwing the air mixture screw in or out 1/4 turn at a time to find where the engine speed is fastest, then adjust the throttle stop to slow it down to a nice even tickover. Often at this age, there is so much wear it can be difficult to get a good even tickover. On mine, I set it at a highish tickover to stop it running lumpy whilst sat at the lights.

Col