I can't remember carbural around the midlands. The use of Redex became a way of life, it was natural to always ask for shots with your petrol, this was in the time when petrol pump attendants where around, no serve yourself in those days. Thinking back, I also remember amongst the petrol pumps where oil dispensers, If your engine was using a lot of oil, and they did in those days either out of the exhaust pipe or dripping from the bottom of the sump,
you could buy a pint of oil and they would add it to your engine. My first motorbike was a two stroke engine, when I bought petrol it had to be mixed with a ratio of oil, hence the reason for oil dispensers, but then came the "two stroke pumps" which mixed it automatically, have we any two stroke engines nowadays ? can,t remember seeing a two stroke pump for ages.
Talking about smokescreens, that A35 van I mentioned earlier, used to do less miles to the gallon on oil than it did on petrol, after a long downhill run you hit the accelerator and wow, the trail of smoke began, we have something to thank for MOTs and legislation these days.
Goffy