Fuel Oil Ratio is the amount of oil in the fuel mixture. Higher ratio means less oil per gallon of fuel and lower ratio means more oil per gallon. Typical motorcycle fuel mix ratios range from 32:1 to 60:1.
Jetting rich and lean (the ratio of fuel to air) is not the same as fuel mix ratio. In fact, in the extreme, more oil actually means leaner jetting because there is less gas in the fuel mix.