I did not see any voltage, but rather a wattage limit, which is 750 watts. You can go over 750 watts, but your bike will become a class three bike, requiring a helmet and possible insurance. Also, I believe the 750 is a federal standard, which makes it compliant with federal law. If I were Golden Motor I would be thinking about how this would affect the sales of 1000 watt motors. this is sort of a forced paradigm shift, and the company that caters to this law, will be the more successful company. I wonder too, how much cheaper a 750 watt motor would be to manufacture and to ship.
I drink Stella beer, and they are 11 oz as opposed to 12 oz - in the case of shipping this really adds up considering the bottle weighs about the same as the beer inside it. I believe a smaller motor would obviously weigh less, cost less to build and ship. Therefore it would be cheaper, and more competitive in a market that is quickly bloating. But I am ignorant as to how difficult this would be to engineer, and how expensive, but taking the long view, it could be worth it.