YAS1 had old-fashioned humpback styling and a tendency to burn holes in its pistons, but was a wild enough little thing in its way. Now very rare. The more powerful YAS3 looks almost classical but could overheat and was very sensitive to ignition timing. Both need a crank rebuild around 20/25k. Good ones now rare.
1969-73, 123cc t/s twin, 15/16hp 75/80mph 70mpg 250lb