Honda CL450 Scrambler Twin 1968-1975 Service Manual

The National Motorcycle Museum's own history of this model doesn't sugarcoat why it exists: the original 1965 CB450 "Black Bomber" struggled commercially in America because "styling got in the way" — its touring-oriented tank and fender design read as un-sporty next to the British and American twins it was meant to compete with. Sales were slow enough that "Honda was driven to ship styling update kits to dealers to convert the machines to sportier high pipe scramblers," with fenders, fuel tank, side covers, seat, and exhaust swapped out right at the dealership as bikes were uncrated. That stopgap measure led directly to a proper factory solution: "by 1968 the refined, well accepted CL450 Scrambler version was launched and sold alongside an updated CB450 Super Sport."

Power comes from the same 444cc air-cooled DOHC parallel-twin underpinning the CB450 street bike — genuinely groundbreaking architecture for its era, using torsion-bar valve springs and twin constant-velocity carburetors rather than the conventional coil-spring valvetrain and simpler carburetion most rivals ran. The 1968 K1-generation update brought a 5-speed gearbox in place of the earlier 4-speed, a larger oil pump for improved warm-up, and a lengthened wheelbase specifically to sharpen handling — genuine mechanical refinements shared across both the CL450 Scrambler and its CB450 street sibling from this point forward. Electric start arrived alongside these changes too, though the Scrambler retained a kick-starter as a practical backup given its off-road-inspired mission.

The Scrambler treatment itself was the whole point: a distinctive high-mounted exhaust system running up the right side of the bike (well clear of water and obstacles on unpaved terrain), a more upright, dirt-capable stance, and simplified bodywork that traded the CB450's touring-styled tank and fenders for a leaner, purpose-built look that finally resonated with American buyers wanting genuine dual-purpose capability alongside street performance. The National Motorcycle Museum's own account notes period drag-strip testing found the CL450 giving up half a second in elapsed time to a Harley-Davidson XLCH, yet frequently posting a higher trap speed — a genuine testament to the little twin's high-revving character even against a larger-displacement rival. This platform ran through 1974, after which Honda stretched the engine to create the CB500T rather than pursuing a genuine redesign, effectively closing out the original 450 twin's run before the 1978 Hawk 400 picked up Honda's middleweight-twin mantle with all-new engineering.