A Honda 400 (CB400) Hawk Twin will do as well though not the 400A Hondamatic (27 HP). All the other variants but the A version., meet your criteria.
About 400 lbs weight. The weight of the motorcycle is also a factor you may want to consider. Keep in mind the claimed figures are often so much gas, and that you wont be experiencing DRY weight, but wet. So figure about 6 pound per gallon of gasoline, and the weight is higher up, so don't stand there with a full tank and wait for disaster. (stop at a stop sign, straddling the dip in the road so your feet don't reach, or stopping on leaves, so your foot slips.