Bultaco was quick to realize there was a ready market for short trackers in the U.S. Short tracking or running Class C type dirt track racers on American dirt tracks was a very popular sport. Enter the Astro. Its frame was set up for quick steering, and it was void of all non-essential components. Ready to go, out of the crate. Many racers carried them along with their bigger racers to pick up a little extra money. Alloy wheels front and rear completed the package revered by many. Included is the notice from the factory that these were fitted with the gearshift and brake lever on the right-hand side. It was not uncommon to find these engines put into Metrallas by enthusiasts.