interesting phenom with different mixtures, oil weighs more than gas, decrease the oil ratio and you decrease the weight of the fuel.... this has a direct relationship to how much volume the vacuum will pull through the jets, lighter fuel means the vacuum will draw more,.. giving richer conditions..
so if you decrease the oil, more fuel goes into the motor....
now a tertiary effect...
the more fuel that goes now has a higher ratio of fuel to oil resulting in even richer conditions, ...
remember its fuel to air, .. NOT fuel+oil to air
(i had to learn all this roadracing 2-stroke triples)
JimS