Re: very bad gas mileage.
Mine got that kind of milage before it was fully broken in as well, and another thing to consider is the advertised 100 to 130mpg is possible but not at full throttle where the engine can consume 2 to 3 times the amount of fuel it does while cruising, add in overly rich jetting from the factory and any extra load like hill climbing, fast take offs, or a heavy rider, or carrying extra stuff etc, it all adds up and takes away from the gas milage.
The best fuel milage will be experienced with the highest manifold vacuum and the lowest engine rpm for a given speed. Of course, trying to read vacuum on a 2 stroke single cylinder is near impossible without some kind of a restrictor in the line and I don't know of anyone who uses a vacuum gauge on their bikes, but high vacuum can be translated to light engine load, so basically, the lower the engine load and rpm at cruising speed, the better the fuel milage will be.
Things like going fast all the time, under or over gearing, riding in hilly areas, heavy riders/bikes, underinflated tires, dragging brakes, bent rims, etc, etc as well as running in a new engine can add up to some really poor gas milage.
Cruising at about 50 to 75% of the bike's top speed with as little load on the engine as possible is what's going to get you closer to those advertised gas milages, providing you're on flat ground, not going against the wind, and your bike is straight and true with properly inflated tires and nothing putting a drag on the bike.