The SL line began quietly enough with the SL90, a tweaked version of the by-then venerable 90cc OHC single that had already appeared in CB and CL versions. That was soon followed by a version punched out 10cc to become the SL100, featuring an all-new frame, heavily revised suspension and of course, more poke. That basic design then morphed into the SL125, a wonderful, rugged little machine that sold like the proverbial hot cakes worldwide.
But these singles were only part of the SL dynasty. The twin-cylinder SL350 lumbered into life in 1969, but was too heavy and ungainly for many to take it seriously as an off-roader, although its road manners were pretty decent. That design gained more points in the K1 version, with things like the vulnerable and heavy exhausts system tricked up, less weight (due in part to the jettisoning of the starter motor), and better suspension. The SL350 in effect was a twin four-stroke in a sea of two-stroke singles, but it had an affable personality, the reliability that had become Honda’s calling card, and to a certain extent, offered two motorcycles for the price of one.
By now the SL range had grown to include the up-scaled mini-bike SL70, but Honda wasn’t quite done with the twin cylinder concept. In the ‘upright’ engine variation of the popular OHC 173cc twin that had garnered big sales in CB form, Honda had a power-plant that had much to offer the market that had lapped up the SL350,
