I think I have seen or tried every trick in the book and here is officially what I have found.
Average for all Valks is 34-36mpg. Sometimes it better sometimes worse but this is the overall average so one just lives with it.
6 carbs are cool but not very efficient as the intake velocity is to low in most cases to properly anatomize the fuel. Fuel injection or the 2 barrel setup like the older GL15's had works better for mileage.
Spark plugs, synthetic oil, fuel brands, air pressure etc - makes no real difference except people tend to "feel" better about the machine.
My average has not changed more than 1mpg and I did the ignition advance and plugs and the works. I figure if I want to get mileage I will just ride the wing or my st. I focus more on ride quality now so I upgraded the tires to bias and car tire and run 34 and 26 psi, I use regular oil and buy gas wherever I happen to stop and just enjoy the soft ride and carry a credit card for fuel - still average 34-36mpg but i "feel" better about it.
