Hi, i'm a noobie to this site. In Dallas back in 1971-72itI was riding a modified kawasaki 100 trail boss.I was riding at a former horse stable and field. On the corner of Skillman & Walnut hill lane. We would regularly have about 10 different bikes there. Suzuki 185, Suzuki 400 MX, a Suzuki twin 2 stroke street bike, Honda SL350 and this one guy brought out 90cc flat track bike with constant loss ignition.Battery only. And it turned high RPM's. it was just a dirt lot, we had a small short track, a hill, some jumps.The property was in early development, today its a shopping center with houses around it.