Or like me if your favourite type of riding is on the old highways in Canada and the US. Sometimes low Octane fuel is all that is available in the little towns.
On one trip thru Wyoming the first fuel available along the route for the day was at the 125 mile mark, most of a tank on the loaded Vincent. The next fuel was 80 miles on down the road, it would never make it
We arrived at the little town only to find out that the GPS info was outdated, the only pumps in town had been taken out a few months earlier.
The owner of the only restaurant in town sold me some lawnmower gas of unknown age and quality. The bike is at 8 to 1 and it ran fine on it.
Now I'm looking at reboring and those 9 to one pistons are so tempting.... but then one of my mates holed his 9 to 1 bike in a similar situation running on low Octane backwoods gas on another trip.
My bike started life in the Isle of Malta at 5.3 to 1 compression in 1947. I guess the fuel quality there was horrible after the war. The bike was presold to a British military man in Malta, so the factory set the CR for that fuel.
It was at 7.3 to 1 when I received it and then I raised it to 8. I'll probably leave it right there. That would be the sensible thing to do....
Do standard 8.9 to 1 750 Commandos run ok on regular in a pinch?
I have run the 850 on regular a couple of times. It measures right around 8.5 to one , no base gasket and a thin version of the composite head gasket.
Glen