(This Retrospective article was printed in the June 2012 issue of Rider Magazine.)
This four-stroke woodser was an immediate hit with the casual rider, and could even seduce two-stroke lovers away from their mounts. As an added bonus the XL350 K1 was quite adequate on the pavement.
For less than one-thousand 1974 dollars anyone could buy this mid-sized thumper and go play on the thousands of miles of dirt roads that traverse this continent. You just had to keep in mind that the 2.2-gallon gas tank liked to be replenished every 100 or so miles, and with a wet weight of 320 pounds the machine needed to be treated with respect.
Tripping down the tree-shrouded byways, where gravel could turn to sand, dirt to mud, the piston in the slightly oversquare cylinder (79mm bore, 71mm stroke) provided a satisfyingly grunty response when the throttle was twisted. The Brits had long claimed dominance in the four-stroke enduro scene, with half-a-dozen companies fielding 350s and 500s in the 1950s. These were good for everything from trials to trail riding. Then the Spanish came along with some razzy two-strokes, and the Japanese, most notably Yamaha, were soon to follow. Four-strokes began to slip away. The Brits were rapidly losing control of the enduro market, with BSA’s 500cc, OHV single-cylinder B50T (for Trail) of 1972 being the last gasp. The Western world was wondering what the Eastern motorcycle manufacturers would do to fill the gap.
In 1969 Honda bore the four-stroke banner among the two-stroke-oriented Japanese. It had tried to market its popular OHC 350 twin as a dual-sport machine, the SL350 Motosport. However, the revvy little engine felt much better on the street than on a forest road. That model lasted for five years, to be replaced by the XL350 single in 1974.
The XL350 was a direct descendant of Honda’s XL250 single. The latter appeared in 1972, and was a pleasant little creature, with the operative word being “little.” The 300-pound 250 was actually quite good in competition, but racing is a very different world from the fun-loving types who just wanted to putter along unkempt trails through a forest, state or national. Honda understood that they could sell a lot more bikes to the fun lovers than to the relatively few competitors, and these folk were more interested in slogging—rather than high-revving—power. To that end the 250, with a chain-driven single overhead camshaft, got bored and stroked to 348cc, and a spin on the dyno showed the 21-incher had well over 20 horsepower at the rear wheel, and almost 20 lb-ft of torque. Respectable.
The same year that the XL350 came on the scene, Honda introduced the XL175 single—250 pounds with 1.8 gallons of gas in the tank. And the miniscule XL125 at 235 pounds appeared in 1975 for riders who really wanted light weight.
Serious enduro types did not need such sissified things as electric starters, so the XL350 had an old-fashioned kicker. But instead of tickling carburetors, retarding sparks, pulling in the compression release and getting the piston just past top dead center, as required by the British, all the Honda required was a big kick. And to pull out the choke if the engine was cold. The four-valve engine’s power peaked at 6,500 rpm, but it could cheerfully spin to 8,000, and a tach kept the rider mindful of engine speeds. The five-speed gearbox had rather wide ratios, good for scrabbling in the muck, and a mere 5,000 rpm was required for cruising along at 55 mph on the pavement. Top speed was said to be about 75 mph.
Particulars for the XL350 were simple. One 32mm Keihin carb sent the fuel mixture into the combustion chamber, where it was compressed 8.3 times, sparked via points electrified by a flywheel magneto, spent gases exiting through a single header pipe that curved under the left side of the engine and into an environmentally friendly, and heavy, muffler. One of the weak points of the bike was that when riding through rocky terrain, the header pipe was susceptible to getting squished by rocks, and a flattened pipe did not help engine operation at all.
The XL350 had a pleasantly large saddle, though no passenger pegs. The vibration from the solidly mounted engine was not a serious problem, but in consideration Honda designed the rider footpegs so that they were isolated by rubber absorbers. This machine was definitely for the semi-sporting enthusiast, though it was street-savvy, with turn signals and all. However, in anticipation of the rambunctious rider Honda made it easy to pull off the turn signals, lights, and take out the small battery.
The frame was similar to the cradle-type that housed the 250, with a single front downtube splitting into a pair of supports running under the engine. A reasonable bash-plate protected the vitals, with about eight inches of ground clearance when a not-too-heavy rider was aboard. The swingarm was extended an inch from the 250’s, for a wheelbase of 55.3 inches, which helped to make the front end a little lighter.
The rear shock absorbers had preload adjustability, the fork none. Wheels used tough alloy Daido rims, with a 3.00 x 21 tire on the front, a 4.00 x 18 on the rear. Brakes had small drums, fine in the dirt, a tad weak in traffic.
In 1976 Honda did a major revamp of the XL350, calling this one the K2, with chassis changes that increased the fork rake to 32 degrees, trail to 5.5 inches. A new cylinder head allowed better intake breathing, and a very neat high-level exhaust system was tucked behind the frame and exited on the right side—taking care of that previously mentioned susceptibility problem on the low-level exhaust. Appreciating the state of the market, passenger footpegs were fitted that were, of course, rubber-mounted. The weight went up to 330 pounds, the price to $1,200.
The K2 had a happy three years, but in 1979 the 350 morphed into the XL500S, which is another story entirely.