A majority of bikes without the additions of fuel injection and electronic controlled processor ignitions using mainly the mechanical speedometer cable could be run this way and I suppose a very small percentage have been. I know that many of these pre 80's vehicles would lose some "niceties" like self canceling turn signals perhaps, as many have said earlier, with no ill effects.
But more likely, the mileage is correct within a few 100 miles, as it is very common that the new bike becomes a garage "queen" because schedules and life styles can change rapidly when we get her home and have this "luxury" item safely bedded down. Part of the problem is the rider with the bike is a "married" couple so to speak, :52: and if not working on the relationship, the bond may recede. Maybe the ride is a little too big and heavy, or without much practice the rider is tentative and the bond never "gels". Also in todays economy that may change as more people come home and those long term trip plans are pulled back.
Motorcycling is a committment of time, health and finances to be sure and some just decide not to accept the risk and trouble to gear up whether it is to the store or that long distance weekday or weekend ride. Statistically, "free recreational time" is being tied up by the media and stresses of more day to day things that distract our activities.:31: