Suzuki For '81

SUZUKI FOR '81

A Late Show, With the Emphasis on Go

Judging by reactions from the dealer audience when Suzuki rolled out its 1981 model line, there's going to be lots of action in the sports and motocross business. The dealers clapped when they saw the new range of 650s, they cheered when pictures of the Katana showbike were flashed on the screen and they whooped, hollered and gave a standing ovation to the water-cooled, solo-shock RM 125.

The good news was a long time in coming. Not in the actual bikes, but because Suzuki’s home plant is expanding and being reorganized, the U.S. offices have expanded and moved and Suzuki is thus the last of the Big Four to roll out the ’81 s. The carry-overs, bikes that aren’t much changed from 1980, were on sale early and that helped some but the really hot numbers like the rumored 650s and all-new RMs, were made public well after the competition had its models in the papers or even on the showroom floor.

Not to dampen the enthusiasm, but in one case what we see here probably won’t be what we get. The GS1 100-based Katana, styled by a German designer and first seen at the Cologne show, appeared for U.S. Suzuki’s national show in slightly modified form. The Katana still takes some getting used to. Different, is the word that comes to mind. The bike in metal looks better than it does in pictures—helpful news, eh?—and it drew crowds. However, company spokesmen said, the U.S. showbike is still more prototype than production. The production Katana will use the GS1100 engine, debored down to 1 OOOcc so it can be raced in the Superbike class. Suspension and bodywork may also be changed but there will be a Suzuki superbike for 1981.

The rest of the line, though, is final. The general theme for Suzuki this year would be an expansion of models, great attention to improving engine efficiency and some overlap in the forms of parallel bikes aimed at divergent markets.

The last can be traced through the designations. The “X” in GS450EX, for example, stands for 1981. In the full factory code, they all have an “X”, just as Suzukis formerly had “T” and “N”. The front letters also continue. GS is for road bikes, RM for motocross, PE for enduro, etc. The letters after the engine size clarify what type of bike it is. For instance, the standard chain drive street models are ended with an E. It’s S for sport, as in the GS450S. If there’s a G instead of the E, then it’s shaft drive. There’s an L for Low Slinger, Suzuki’s interpretation of the customized look with high bars, stepped seats and fat rear tires. And finally there’s a T model in two of the sizes. The T models blend some of the best styling of the L and the E models and we’ll say the T stands for Tasteful.

The largest announced Suzuki, the GSI 100E, was an early release and was in fact tested here in the March issue, so it needs little comment except perhaps that it surely is comfortable for such a fast bike and fast for such a good touring machine.

The 850/1000 line has been rationalized some. The GS850GL and GS1000GL are, as hinted, the Low Slinger models and the GS850G and GS1000G are more conventional. All are shaft drive, as Suzuki decided that buyers who prefer the lighter chain drive system were more likely to opt for the GS1100 anyway. The engines are nearly identical in feature, with the 850s having a bore and stroke of 69 by 56.4 mm and 8.8:1 compression ratio and the 1000s being 70 x 64.8 mm, with 9.2:1 c.r. The G models share a wheelbase of 59.1 in., have 5.8 gal. tanks and come with 3.50-19 front tires and 4.50-17 rear.

The 850 and lOOOGLs have a wheelbase of 59.4 in., due to the slightly kickedout leading axle front ends, and have 4.5 gal. tanks. Tires are 100/90-19 front and 130/90-16 rear, tubeless.

All four bikes have triple disc brakes, air-assisted forks and rear shocks with four damping and five pre-load positions for the springs. Claimed dry weights are 536 for the 850GL, 540 for the 1000GL, 558 for the 850G and 562 for the 1000G. Why the Ls are lighter than the Gs wasn’t apparent. Testing will tell.

The 750s come in L and E models. The 750 Suzuki Four is virtually second generation, as the four-valve, TSCC motor appeared as smaller brother to the 1100 and replaced the original two-valve 750 last year. The sports vs cruiser distinction shows up with E getting air-assisted forks and variable-dumping shocks, while the L doesn’t. Again, sports tires, 3.25-19 and 4.00-18 for the E, 90/90-19 and 130/90-16 for the L. The L has a lower rider seat and higher passenger seat, tank capacities are 5 gal. for the E, 4 gal. for the L. Wheelbase of the 750GL is 60.12. in., longer than the 850s and 1000s due to the 750’s extended front end and again, the L’s dry weight is listed as 507 lb. and the E’s is 514 lb.

Big road news from Suzuki is (are?) the 650. There are three designations of 650, the E, the G and the L, and they are really different.

Top end of the 650s is another new idea.

It’s double overhead camshaft, but with two valves per cylinder, like the original four-stroke Suzuki Multis and unlike the new-for-1980 Fours. Twist here—pun intended—is that the combustion chamber is machined to have two shallow domes, rather than the conventional one. This reduces the volume of the chamber while allowing flattop pistons and giving a wide squish band. The result, the engineers say, is that the engine can run a higher compression ratio, 9.5:1 in the 650’s case, and still use what passes for good gas nowadays.

The 650 is more than that, the 62 x 55.8 mm bore and stroke providing 673 cc. The engines also share a bank of 32mm CV Mikunis.

Now things get complicated. The 650E has chain drive and is at least in part a larger version of the 550 Four, with roller bearing crank.

The 650G and GL have shaft drive. This called for a different lower end as well and as part of a continuing factory program that means a plain bearing crank.

And the shaft drive is different. Most shaft systems, including the others from Suzuki, have a gearbox mainshaft, with clutch at one end, then a layshaft and then an output shaft with bevel gear driving the shaft to the differential.

The 650 shaft drive, though, has the bevel gear on the mainshaft, opposite the clutch, so the gearbox is shorter and 5th gear is direct. There’s a cush drive outboard of the bevel and the whole idea that when you have fewer connections you have less lash and less slop and smoother operation all around. A 650G will be delivered here in time for the May issue and we can hardly wait.

Back to features. The E, Sports model, has no-assist forks and rear shocks with automatic dual-rate damping. It has sports tires, 18 and 19 in. The E and the G share a 5-gal. tank, a 56.5 in. wheelbase and triple disc brakes. The G has 19 and 17-in. tires, tubeless, gets air caps for the forks and adjustable damping in back. The L has leading axle forks, no caps, single rate and fixed damping shocks and 19 and 16-in. tires, tubeless. The E is lightest, 450 lb. in the book, but although the G has one more brake than the 650L and the other Ls are lighter than other Gs, the 650G and L are both listed at 472 lb.

The G and E are particularly sharp, while not being identical. When Suzuki gets into the 650 field, they go all out.

Which is not to slight the 550 class Suzuki revitalized. The ’81 550s are two, the T and the L. Here the T should stand for Tasteful, with painted fender and reasonable bar height and slight seat step. There’s just one engine, dohc, two valve. Final drive is chain. The T and L have the same tank while the wheel sizes are 19 and 16 for the L, 19 and 17 for the T. The L has one in. longer wheelbase, 57.7 to 56.7 and both are supposed to weigh 452 lb.

Last year the GS450S was a big winner, in sales and with the critics. The mechanicals aren’t changed much and the twovalve dohc Twin is shared by four, yes four, models; S, with fairing, low bars and GTstyle tank and seat; E, same bodywork but with higher bars and no fairing; T, mild seat step and teardrop tank, and L, smaller tank, higher bars, different seat. All four have the same suspension, the same disc/drum brakes. E and S have 18in. wheels, the T is 19 and 17 and the L is 19 and 16. (The tire companies must go crazy with all these sizes.) Wheelbases and weights are 54.5 and 384 for the T and L, 54.3 and 386 for the E and S.

Entry level bikes are represented in the road Suzuki line by the GS250T. This is the keen little Twin with four-valve head and TSCC and nicely done teardrop tank.

It looks the way the new rider expects a motorcycle to look and it has all the proper equipment as well as an up-to-date engine.

How quickly things change in motocross. Seems like yesterday that single shocks and water cooling were the exotic stunts the works bikes had and the rest of us had to sneak under the fence to see.

But here’s the RM 125 and it’s water cooled, making that three out of the Big Four, and it has a single rear shock, four out of four.

The RM 125 will make news in other ways. The engine is new, how close to works we won’t know until the test scheduled for next month, but it will be close. The advantages of water-cooling are that more power can be pumped out of the engine, for more time, so surely the 125 will have lots of power. The engine is perfectly square, 54 by 54 mm, and has a compression ratio of 8.5:1, a 32-mm Mikuni, electronic ignition, six speeds and primary kick start. Tank capacity is 1.7 gal., wheelbase is 56.7 in. and claimed weight is 194 lb., right on the limit.

Front wheel travel is 11.2 in., from the non-obligatory leading axle, air-assist forks. Suzuki’s solo rear shock, known as Full Floater, has the vertical shock’s lower mount on the swing arm. Aft of the mount is a pair of links, connecting to a rocker arm that pivots on the frame and has its other side fixed to the top of the shock. As the swing arm rises and falls, the angle of links to rocker and rocker to shock change. Presumably this gives progressive, risingrate spring and damping stiffness. It’s the same idea as Honda’s single shock is and Kawasaki’s is supposed to be. If it delivers the benefits we’ve seen from the Honda system, it will be competitive. There are four damping settings and a range of preload for the spring. The swing arm and all the parts are aluminum and wheel travel is 12.3 in. Super looking machine and early examples, in Team Suzuki’s professional hands, are already winning.

The RM250 and RM465 look nearly identical. Both models are new, of course and they share some components and specifications. Wheelbase is 57.5 in., wheel travel is 11.2 in. front, 12.7 in. rear, tank capacity is 2.4 gal. Both have the single-shock Full Floater suspension. Forks are different. The 250 has 38-mm stanchion tubes and the 465’s are 43 mm. The frames are the same design but the 465 gets larger tubing, which goes right along with the extra power and causes the weights to be listed as 212 lb. for the 250 and 225 lb. for the 465.

The engines are unalike beyond displacement. The 250 has a bore and stroke of 67 x 70 mm, undersquare as the former RM250 was. Compression ratio is mea-> sured in the usual Japanese way, that is from when the piston covers the exhaust port and compression begins, rather than the western system of measuring from the bottom of the stroke. The 250’s c.r. is 7.7:1.

The 465 has a bore and stroke of 86 by 80 mm, oversquare. Its compression ratio is 6.6:1. Whether this comes from deliberately de-tuning for more controllable power at low revs, or because the exhaust port is timed to give power at the upper end, which also means less low end, we won’t know until we have the engine on the ground. We’d guess now that Suzuki figures, like Honda and Yamaha, to give the open class rider all the power the excellent suspensions can handle.

Both the 250 and 465 have what Suzuki calls Full Reed intake system. Ad language aside, it’s an eight-petal reed valve feeding the cylinder, that is, the piston ports, and the crankcase, and the transfer ports from the case into the cylinder. The incoming air/fuel mix flows more of the time while the valves stop any reverse flow and allows port timing that works at peak without interfering with low end power. Again, boost for top end.

More more-is-better for the play rider, in the form of the DR500 and SP500. Like the 370s and 400s before them, the new Suzuki four-stroke is the same basic machine with road gear—Street Practical— or enduro style lights, full knobbies and the name of Dirt Racer.

The 500 Single is a new engine. Bore and stroke are 88 x 82 mm, compression ratio is 8.7:1 for road and dirt. Carbs are Mikuni CV for the emissions-certified SP, Mikuni slide valve for play. The engine has single overhead cam with four valves and TSCC, and dual counter-balancers. Unlike the other big Single with similar specs, the Suzuki 500 has only one exhaust port and a full-cradle frame. The DR has some extras, like wheel travel of 9.1 and 8.5 in. and aluminum swing arm. The SP figures are 7.7 in. for both wheels. Wheelbase is 57.5 in. for the DR and SP—odd, seeing as one has more wheel travel and ground clearance than the other. Maybe the steel SP swing arm longer—and the chart says weights are 283 lb. for the DR, 305 for the SP, in case you wondered how much lights, signals, etc., add.

In sum, a good show. If the new models took a while to arrive because the factory was getting ready for extra order$, chances are things will soon be back in balance, with orders to keep the factory busy.