THE HONDA SL350
TONS OF FUN
By Matt Cuddy
I know, you’re thinking “oh jeez, he’s gonna roast this bike” but not this time. The Honda SL350 was a bike that defied all odds. By 1969 the formula of a street-scrambler didn't cut it anymore, so in 1969 Honda responded with a new design of its beloved 350 twin, the SL350. The production bike was overweight, over styled and had a tendency to spit riders off like watermelon seeds, but the Honda SL350 had one thing going for it: The motor.
1969 K model SL350
The SL350 started life as a styling exercise aimed to cash in on the burgeoning dirt bike craze of the 1970’s. Sharing the frame and electric start motor of the CB/CL series, the first SL350 brought out in 1969 was nothing more than a CB350 with off-road down pipes, and cross braced handlebars. The CV carbs of the first SL’s had the bad habit of its slides slamming shut when a bump was encountered, as the weak return springs of the constant velocity Kehins couldn’t compensate for inertia or gravity. This annoying problem caused many a hill-climb attempt, or trip through the whoops to be scrapped as the rider picked himself up from the dirt, and asked himself “whatinthehellhappened?”
In 1970 the SL350 got a new double downtube frame, and the electric start was scrapped, making the motor unique to the Sl series. A 19inch front wheel, and competition designed lightweight cast aluminum fenders (!?) graced the SL350, and brought its weight down to a svelte 368 lbs, wet.
1970-1971 SL350K Notice electric start gone, and frame change.
The 1972-1973 SL350 got a 21 inch front wheel, and the painted fenders got polished into blinding sun reflectors, that constricted pupils into pinpoints on hapless SL350 riders. The bike still tipped the scales at over three hundred and sixty pounds, and the skinny 21 inch front wheel, with a 2.75 Nitto trials tire made riding the bike in sand a truly futile proposition, as the front wheel knifed in at every opportunity.
1973 SL350, nice fenders
The motor was EXACTLY the same as the CB & Cl models, same camshaft, same crankshaft, ignition, gearbox, etc. The only difference was the final drive gearing, and exhaust systems. The later SL’s had standard Kehin 24mm carbs that eliminated the aforementioned CV’s slide issues, and with a more restrictive exhaust system, brought the SL’s power down to 30 horsepower, from the CB’s 36 horsepower at 9000 rpm, and the CL’s 34 at 10,000 rpm.
And what a motor it was. The 350 Honda twin was anvil reliable, with over 300,000 copies being sold in the USA alone, it was one of the most popular motorcycles ever produced. When the SL350 got some knobbies strapped to it, and decent shocks bolted on the back, the bike became an unstoppable woods weapon, as nothing short of an atomic blast would cease the rear wheel from spinning. It was also, in my mind one of the best looking vertical twin cylinder motors ever produced, right up there with a Triumph or BSA in the looks department.
In 1974 the SL350 was replaced by the XL350, with the CB & CL being replaced by the 360 twin, a relative failure when compared to the 350. And you can still find a nice example of the 350 twin for cheap, since the 350 is still not recognized as a true “classic”. Here's Senior Editor Rick Sieman's take on the mighty SL350:
Somewhere in the mid-1970s when I was the editor of Dirt Bike magazine, we got a Honda SL 350 delivered to the offices. When I pushed the bike up onto the loading ramp to take it to the garage, it felt like it must have weighed 400 pounds. Later on, I looked at a spec sheet and it was right around three sixty-something. My immediate reaction was that it was a real pig.
I was getting ready to head out for an enduro in Ohio at the time and just assigned one of my assistant editors to do up basic sort of test on the bike. I believe my thoughts were, “Why don't you take it down to Van Nuys Blvd. and cruise up and down the street, because that's what it was obviously made for?"
When I got to southern Ohio for the enduro a few days early, I had a chance to ride some of the neat woodsy terrain. The guy who laid out the enduro was riding, of all things, a Honda SL 350. Most of the crap had been stripped off the bike and he had plastic fenders and a short set of down pipes with Snuff-or-not mufflers on the end of the bikes.
I asked him how in the hell could he ride that heavy twin cylinder four stroke in the deep woods. He said that while the bike was indeed heavy, it was as close to bullet proof as any motorcycle he had ever owned. I was on a 175 Penton and had to ride good and hard to keep up with that 350 Honda.
Later on, he let me ride the bike, and I was more than impressed. Sure, it was heavy, but the motor had tons of power all throughout the range, shifted good, started easy, it didn't handle all that bad. Surprise was a very mild word to use at that point.
When I got back to the magazine after the enduro, I had whole different bunch of thoughts about that particular bike. Instead of writing it off as just another Japanese experiment gone wrong, I started to see the virtues that the bike did have. It was inexpensive and almost indestructible. And you know what my dear friends? In that day and age, it was worth the price of admission.