LFR--okay, take the average mileage you're quoted, cut it in half.
And if you can't drive a car, you sure as shit can't ride a bike. Personally, I'd love to watch you try to come up to a light, either not pulling in the clutch, stalling, and dumping it (and unable to get it back up) or better still, mixing them up and going flying through the intersection and turned into a greasy road pancake.