Suzuki Gt380
Cycle World Road Test
SUZUKI GT380
Tried and True If Not Quite New
PROGRESS DOESN'T LAST forever. Back in 1972 Suzuki had a new idea: Take the latest in superbike technology. Scale it down here, beef it up there and you'd have a pleasant combination of touring, sport and commuting, all for an attractive price.
So they introduced the GT380, a twostroke Triple with features like Ram Air, a six-speed transmission and enough room for comfortable two-up touring. Late in that first year they added a front disc brake. A bit after that Suzuki re-did the frame and exhaust system to provide more ground clearance and reduce vibration. The GT380 was a 1972 motorcycle that looked like a 1972 motorcycle. Pretty nice, said Suzuki to itself, now let's tackle another project.
Here we are, then, with the 1976 GT380, an old friend in several ways. We also have a puzzle, in that the GT380 is still a 1972 motorcycle while its rivals in class are not. That may be a drawback. And it may be a subtle way for Suzuki to get a good return on its investment.
But first, mechanical details. For its dis placement and power the 380 is a big engine in terms of weight and dimensions. It's a normal two-stroke Triple except that first, it has the Ram Air system developed for Suzuki's road racers. Simple design-an air scoop ducting cold air directly across the cylinder head-and a good design in that it works. The 380 is not susceptible to the power loss most two-strokes suffer during a long, hard run. Second, the oiling system is complex, a dual affair. The pump feeds oil directly to the lower end, after which it's mixed with incoming fuel in the crankcase, and a second delivery system works as an autolube to mix gasoline and oil before delivery to the crankcase. Naturally the calibrations are set so oil consumption is about like any other two-stroke's, while giving the rotating parts some extra protection.
As a sort of subfeature, the 380 is tuned foi the long run. Porting, timing, compression. carburetor size, etc., are all chosen to delivei smooth power at the expense of maximun power. The 380 Triple is as big and heav) as a four-stroke of equal displacement. It's also as strong and reliable as a four-stroke ol equal displacement. Fair enough.
Frame and chassis make the GT380 some thing of a big medium-size motorcycle. Again, it's long and heavy for its power and displacement. Suspension is entirely con ventional and a touch out of date: the combination of too much stiffness and not enough control we expected back in `72 and don't always expect in 1976.
The other side of that coin is that the GT380 is large enough for two normal people. The saddle is deep and long, the passenger pegs are a good distance from the rider's pegs, there's enough space behind the seat even for a luggage rack.
How does this all work? Very pleasantly. The 380 fires up and displays no tempera ment, hot or cold. Spark plugs don't foul, the 380 will idle without loading up, the power band is nearly as wide as the rev range. A small blue cloud under full power and a thirst for fuel out of proportion to the engine's power and displacement are the only signs-okay, the noise as well-that the 380 is a two-stroke.
Complementing this nice engine are the transmission and gear train. The clutch is easily controlled, and the shifts, while per haps on the notchy side, are quick and precise. The six speeds are provided to get the most out of the engine, and they do, but keep in mind that the powerband is broad enough to allow a choice of gears for virtually any condition. Sixth is naturally a cruising gear, good for the freeway or long> flat stretches. On slight grades or a crowded highway when the rider may need power in hand for lane changes and avoidance maneuvers, fifth will work all day with no feeling of strain and not much extra fuel rnnsiimntinn Gnntl fnr S11711k1
Handling is best described as being excel lent within the GT380's limitations. As it comes from the factory the GT380 is stable and steers well. The ride is harsh. Little bumps and jars reach the rider directly because the suspension does not react prop erly, indeed hardly reacts at all, to small irregularities.
This isn't much of a problem. The cure is described in the August CW, but in brief, the front forks benefit from softer springs, more rebound damping and longer travel, while the rear receives better shocks and softer springs.
SUZUKI
GT 380
$1350
Meanwhile, the GT380 is predictable and sporting up to a point. At touring speeds the rider is more apt to notice the comfort than anything else. Twisting the grip farther brings on a wobble, the impression that the rear suspension is shifting its feet as it pre pares to brace itself against the road. Cor nering force tries to skew the wheel in the swinging arm and the swinging arm in its mounting. Some of this force does shove the tire about, which the rider can feel. This is not so much a big thing as it is the GT380's way of telling you you're going fast enough. The second warning system is more force ful. Presumably because Suzuki has a fond ness for symmetry, the three-cylinder engine has four exhaust pipes and tour mufflers, the middle cylinder having two smaller pipes, one on each side, below the mufflers for the outer cylinders.
There is a problem getting all this hard ware and the pedals, stands and such tucked out of the way. As a result, they are not tucked out of the way and the lefthand side of the center stand grounds before the bike is leaned as far as the tires and suspension would otherwise allow. Normal riding, no problem. Ride hard or push through a twisting road and the GT380 is likely to scrape. The third and final warning system in volves the footpegs. The 380 is a wide engine. The pegs are naturally outboard of the engine and the pegs are wide. Further, they are rigid, that is, they do not fold if they scrape the ground, and they will scrape the ground under maximum cornering. This is not a good thing. The rigid peg can become a pivot point for the bike, while a folding peg will not dig in. We did ground the pegs during the test and we were not riding at high speed. So. The GT380 has some limitations to its sporting nature.
Much the same for ergonomics, the art of making machines fit people. Riding position is acceptable, i.e., tall and short staff riders agreed the handlebars were fine, while the taller chaps found the pegs too high and too far forward and the short guys didn't notice. The seat was fair, one up or two: An hour in the saddle was plenty, although in fairness that's about standard for any massproduction bike of this size and type. Okay. What we have here is a good big middleweight. Tried and true. The engine, transmission and such have been in produc tion for a long time and all the bugs are out. We know it's a reliable bike with adequate performance, more-than -adequate comfort, lots of room. The GT380 is a machine on which any of the staff would cheerfully set out for a long ride, and there aren't many bikes in this class about which we would say that.
However. Suzuki's research has been more visible than its development. Virtually the only truly clever item on the GT380 is the vacuum-operated petcock and that's been a Suzuki standard feature for a couple of years. The digital read-out for gear position is the sort of thing the salesman likes to point out, but an owner doesn't need it after a day or so, and in any case, the light is too dim to be read in sunlight.
During the four years this model has been on the market the market has changed, and the GT380 hasn’t. The potential buyer is likely to look around and notice the Honda CB400F, the Yamaha RD400C, the Kawasaki KH400. He’s apt to realize that the other bikes in class look new and clean while the Suzuki looks dated and fussy. He may wish for items like collector exhausts, cast wheels, self-canceling turn signals, and electric starting which rival bikes offer and the Suzuki doesn’t.
More to the point, the others are in general lighter, more powerful, faster, better handlers. They even in some cases cost less money. The other factories have been working on new motorcycles. Suzuki has been building GT380s.
Suzuki is capable of innovation, of sound engineering and invention, of attention to detail. The GT380 has not received the effort Suzuki could give, the effort required to make it a competitive model.
Why not? Surely because the trend is going away from smallish two-stroke Triples. The various rules in force now and looming in the future will see to that. A model year or two from now, there won’t be any two-stroke Triples for the road. It follows that Suzuki has chosen to meet present demand only, at minimum investment, while putting the engineers and designers to work on other projects.
One cannot fault them for this. Persons in the market for a two-stroke Triple in pleasant, semi-sporting form might think hard about the GT380, ’cause if you don’t buy one now, you will lose the chance.
For other buyers, the GT380 is like going to the movies with your sister: Nothing wrong with it, but more exciting alternatives spring readily to mind. Q
$36
Rear turn signal lenses are now amber for greater visibility. Taillight is dual bulb unit for brightness, tail pipes collect unsightly "mung" on tips when using a low-grade injection oil.
FRONT FORKS
Description: Suzuki 380 fork, HD-315 oil Fork travel, in.: 4.5 Spring rate, lb./in.: 37 Compression damping force, lb.: 8
Rebound damping force, lb.: 12
Static seal friction, lb.: 12-14
Remarks: Rough roads jar the rider and. concrete seams on freeways are annoying because the suspension does not react properly to small surface irregularities. The reason is excessive spring rate. A 26-lb. spring with 1 in. of preload is the cure. Compression damping is fine but rebound is way too light. Heavier oil is not the way to go because it would increase compression damping as well as rebound. To fix this, braze the upper rebound hole shut on each damper rod and file smooth. This will increase rebound damping by roughly 50 percent, which is pretty close to what is needed.
REAR SHOCKS
Description: Suzuki 380 shock Shock travel, in.: 2.5 Wheel travel, in.: 3.0 Spring rate, lb./in.: 133 Compression damping force, lb.: 15 Rebound damping force, Lb.:
Remarks: The damping curve on the stock. shocks is not too bad, but rebound is a little heavy. Travel is minimal, which pretty much prohibits use of a more appropriate, softer spring. Because of these limitations, we suggest replacement. Koni is one good choice. The part number is 76F1307. With this shock a 90-lb. spring should be used. Boge Mulholland makes a good shock for the 380 that is adjustable in terms of com pression and rebound damping. The part number is SS1175. Boge recommends 811100-lb. progressive springs. Recom mended spring rates are for solo riding.
Tests performed at Number One Products
