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Two-Wheel Tuesday: Suzuki GT380

Craig Fitzgerald September 4, 2012 Two-Wheel Tuesday 11 Comments

Suzuki GT360

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We Americans are a strange lot. The only thing we seem to care about is displacement. Whether or not a small displacement engine can wring out more power and better performance, all we give a rat’s ass about is that the emblem on the fender or the side cover is bigger than somebody else’s. That — and encroaching regulations about emissions — are what kept two-stroke motorcycles like the Suzuki GT380 out of everybody’s garage in the golden era of motorcycling.

In the ’70s, big-displacement motorcycles were the shit. Within a few years, every Japanese manufacturer would have engine displacements in four digits, and some tested the waters with massive six-cylinder plants. Yet most Japanese manufacturers (Honda was the notable exception) were still wedded to the two-stroke triple as a method of providing the budget-conscious rider with a motorcycle that still had the power of engines nearly twice its size.

Suzuki was perennial second-chair to Honda’s two-wheeled onslaught of product. The GT range was Suzuki’s answer to the CBs at Honda: practical, nearly flawless motorcycles that weren’t just transportation (like the upcoming “Universal Japanese Motorcycles” of the 1980s), but also allowed for a bit of performance and panache. 

The GT was comprised of widow-making, watercooled two-stroke triples like the GT750, as well as the smaller-displacement, air-cooled cousins, the GT500 and the GT380.

Liquid cooling was the wave of the future. Suzuki’s “Water Buffalo” eliminated the biggest problem related to high-revving two-stroke engines at the time, namely the loss of power associated with piston-seizing combustion temperatures.By circulating cooling water through the engine, these Suzuki two-strokes could have pointed the way to incredible streetbike power. The only thing holding them back — even in the smog-hazed 1970s where you could drive a Volvo diesel that painted the rear hatch black with soot — was emissions. 

The GT380 and GT500, were still air-cooled. While it was making such a big splash with water-cooling, Suzuki needed to come up with something for its air-cooled bikes so that they didn’t look like they had so much of a disadvantage. The answer was the “Ram Air System” featured on the GT380 and GT500, the name prominently displayed on the sides of the engine. Pontiac’s idea for Ram Air was to force cool air into the carburetor. Suzuki instead routed cool air to the top of the cylinder head to keep the engine from frying itself way up into the 7,500-rpm redline. Cynics looked at the Ram Air System as nothing more than a bent cookie sheet atop the cylinder head that forces air across the cooling fins. That’s not entirely fair, because if you compare Suzuki’s engine design to that of Kawasaki’s two-stroke triples of the time, Suzuki’s engines were topped with an angular cylinder head, paired with an air scoop to maximize the flow of cool air.

If it was balls-out, rectum-clenching power you wanted in the early 1970s, Kawasaki was the weapon. The GT line from Suzuki was more sedate and grown-up than the mouth-breathing Mach III from Kawasaki. Bike magazine in 1976 said the GT for had a “vast acreage of usable power, spread from anything over three grand right to the redline.”

At the same time, the magazine also griped about the lousy suspension and bubble-gum welds. The best quote of the article suggested that the frame looked “like a collection of tubes holding two wheels apart, tacked together with aesthetically repulsive gusseting.” Hey, sign me up!

Never mind the period critics, though. All Japanese motorcycles of the era flopped around on flaccid suspensions, and for all the talk about Honda quality, their welds were a long ways from a row of perfectly spaced dimes. Today, 1970s-era GT bikes from Suzuki are starting to get their fair share of attention among people who appreciate the Japanese brands.

These bikes are plentiful and fairly inexpensive, and they represent an interesting window of motorcycle history that was quickly being slammed closed and painted shut. By the mid-1980s, only Yamaha would produce a road-going two-stroke, and the awesome RZ350 would be the last of the breed.

  • Great article. I rode a 1974 GT550 for five years, and loved it. It really was a nice bike, and I should have kept it when I moved to Arizona. It was reasonably quick, handled well once I put heavier viscosity oil in the forks, and was just smooth as silk. I got rid of the airbox and put foam air cleaners on the carbs, which gave it a little more torque and a real neat intake noise. The two stroke ring ding at idle was amusing, and the sound at full throttle was just music, even if you weren't actually accelerating at warp speed. Every spring I'd take the exhausts apart (two big mufflers for the outside cylinders, one on each side, and two little ones for the inside cylinder, under the big ones!) and clean the nasty black oil sludge off the baffles. One real neat feature of these Suzukis was the oil injection pump that worked off a cable from the throttle: at full throttle the pump ran wide open, at part throttle or idle it fed just enough oil to keep the bearings happy. The bike didn't smoke all that much, considering the fact that it was a two stroke. You just kept an eye on the oil tank, and topped it off periodically. The only time it would really smoke like crazy was after about a week of sedate riding in town, getting on a freeway on ramp, cranking it wide open and banging through the gears would heat up the mufflers and burn the oil out and create a very impressive smoke screen. I'm sure it made hippies cry. Yeah, I miss that bike, even if the instrument cluster was falling apart and parts were getting hard to find.

  • Irishzombieman

    Great read, Craig. How did I not know about these before?

  • JayC

    I enjoy these trips down memory lane, thanks Craig. I need a two-stroke!

  • Number_Six

    Pedant alert:

    Streetable two-stroke bikes were produced until around 2002. I believe the Aprilia RS250 may have been the last one. Here in darkest Icehockeystan we had two-stroke bikes late into the 1980s, if not after that. My last oil-burner was the bonkers 1986 Suzuki RG500. It and the equally cool Honda NS400 were not sold in the US.

    Having got that out of the way, good read and fun little bike.

    • Irishzombieman

      The NS400 has always been high on my list of toys to buy when I get rich. And now, so is the RG500. Yeow!

      • Number_Six

        My first bike was a Suzuki RG250 and when I upgraded to the RG500 I had to decide between it, the NS400, and the Yamaha RZ500. The RZ500 was probably the best all-rounder of the three and the Honda wasn't nearly as quick as the two 500s, but what a time to be shopping for a sporty bike! I wish I'd kept the Suzukis but they were really finicky and weren't much good for anything other than shocking four-stroke riders on track days. Now I'd really just like something like the GT380 for putting around town.

  • GlassOnion9

    Hey! Finally an article about something I actually OWN!

    Not that my GT380 runs.
    But it turns over. That's more than could be said for it when I bought it!

    Someday I'll finish fixing her up and get her out on the road. <wistful sigh>

    • Number_Six

      Do it! Post pics!

    • I hope you enjoy gapping and timing three sets of points as much as I did. And no, Boyer doesn't make an electronic ignition for Suzuki triples. I learned that a long time ago.

  • <img src="; width="500">
    Another example of '70s Japanese welding prowess, the '76 YZ125C swingarm I'm using as part of Bultakenstein. Yes, those are factory welds.

  • Steve C

    GT550 Not GT500 the 500 was a twin.

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