I have fitted a brand new Zenith Carbm onto the old girl. However, she is smoking heavly... so i took her to Sanspeed in bexleyheath for a tune-up thinking the timing must be out. However, after returning they said the timing/ignition is fine and the carb is running super rich - which is causing the smoking. Said they have turned the carb setting to super lean and no change. they said the Carb is knackered and buy a new one or, the diaphram (the one with 3 screws on the top of the Carb) could be at fault. I looked at this and it is ok.
I don't want to throw good money after bad. What should i do?