Yamaha XT 600

You can't help but feel sorry for dual-purpose motorcycles. They've become trapped in a world they never built, saddled with a jack-of-all-trades, master-of-none role in an era of ever-increasing specialization.

It wasn't always this way. Back in the old days, there were no such things as specialized motorcycles, or even dual-purpose motorcycles. In effect, every bike was an a//-purpose machine. You took the lights off of your street bike and stripped some weight if you wanted a cowtrailing machine. If you took off even more weight, hopped-up the engine and put on the appropriate tires and handlebars, you had either a road racer or a scrambler. And a touring bike? Well, that was the same basic street machine with a duffel bag strapped to the rear and some sort of aftermarket, handlebar-mount windshield up front.

Just like those bikes of yesteryear, today's dual-purpose motorcycles can do just about anything. It's just that they suffer anytime they're compared, one category at a time, to any of the specialized bikes. Yes, some dual-purpose machines can be used for long-distance touring, but compared to gliding along the highway on one of the big touring bikes, doing so is an ordeal. Off-road, a good rider can take a dual-purpose bike almost anywhere, but an equally skilled rider on a proper dirt bike will get there sooner with less effort—and fewer crashes. On twisty backroads, dual-purpose bikes account for themselves amazingly well, but a good sport bike remains a far better choice for doing Kenny Roberts imitations.

Still, dual-purpose motorcycles seem to maintain a small but loyal following of riders who believe in the one-bike-for-all-uses concept. And the prestige class for dual-purpose machinery is the big-bore division, bikes that displace from 500 to 600cc. Yamaha's entry in that category is the XT600, a 595cc thumper that can trace its lineage back to 1976 and the TT/XT500 models, the first modern reincarnation of the classic large-displacement, single-cylinder four-stroke.

As Yamaha's dual-purpose flagship, the XT has all the latest tricks. Styling, of course, is heavily biased towards the dirt side of things, which is apparent in the high-mounted plastic fenders front and rear. A red, motocross-style "safety seat" sweeps forward onto the gas tank to cushion a rider's delicate parts. The sidepanels and headlight cover have blacked-out panels meant o resemble number plates. There's a tool pouch mounted on the rear fender just like on the real enduro bikes. There are even air shrouds attached to the bottom of the gas tank, which seems a trifle gimmicky, although Yamaha claims they direct cooling air to the engine. But it's hard not to believe that the black plastic shrouds are there to resemble radiator shrouds. And, in fact, quite a few observers asked, "Water-cooled, eh?" as they gave the air-cooled XT a quick once-over.

There are other, non-gimmicky components on the XT600, like the open-cradle frame that closely resembles the one used on the dirt-only TT600. A substantial aluminum skid plate in the classic coal-shovel pattern protects the bottom of the engine from rock damage. The front fork assembly has 41mm stanchion tubes (down 2mm from the TT600's), air caps and 10 in. of travel. An impressively strong front disc brake easily hauls the 600 down from highway speeds yet is still controllable enough for effective use in the dirt.

Yamaha went all-out on the XT's rear suspension. Gone is the 550's old-style Monocross system that placed the shock in an almost-horizontal position above the engine, replaced by a lower-mounted shock and a link system that provides for progressive springing and damping rates. The bottom link pivots, as well as the swingarm pivots, have grease fittings, while the top pivot, where the shock attaches to the link, is protected from wheel-thrown debris by a pleated rubber boot. The shock itself is adjustable for both spring preload and rebound damping, and the adjustments are easily made at the lower end of the shock. Rear wheel travel is 9.3 in.

A nice touch is the aluminum box-section swingarm, lighter and better looking than the customary silver-painted steel unit. The arm pivots on needle roller bearings. Snail-cam chain adjusters and a quick-detach rear wheel make chain-tightening and tire-changing duties easier.

Power to move the XT down the road or the trail is provided by an engine that follows the modern thumper pattern. A single

overhead camshaft opens and closes four valves via rocker arms. Exhaust-valve size, 31mm, is one millimeter larger than on the 550 engine, but the engine's 84mm stroke is the same as the 550's. The 600's added displacement comes from increasing the bore to 95mm. The compression ratio is 8.5:1, the same as on the XT550.

As a weight-saving measure, Yamaha fitted the XT with a chrome-plated aluminum cylinder liner (the same as on the TT600) instead of a more-conventional iron liner. We've heard reports that some TT cylinder liners get out-of-round easily, causing oil consumption to go up. Some TT600 owners even have resorted to installing iron liners. When asked about the problem, a Yamaha spokesman said out-of-round liners and oil consumption shouldn't be a problem if the bike is broken-in carefully.

Instead of a single exhaust header pipe, two smaller pipes exit the cylinder, curving to the right before merging into a larger-diameter pipe that leads to a heavy-looking (but quiet) muffler under the right sidepanel.

Like most of today's big four-stroke Singles, the XT uses a dry-sump oiling system, which requires a separate oil tank. But instead of using a frame tube or backbone as a reservoir, the XT600 has a metal tank hung off the left side of the frame, tucked underneath the sidepanel. Yamaha explains that this type of oil tank was used to help achieve a lower center of gravity (the XT550's oil is carried in the backbone above the cylinder head), and to keep the hot oil away from the steering head, where it shortens bearing life. We never had any problems with the tank on our test bike, but an XT owner who rides a lot in rocky terrain would be well-advised to keep an eye on the tank, since it can easily get punctured by a fall onto a sharp rock.

The XT600 uses a dual-carburetor setup, dubbed YDIS for Yamaha Duo Intake System. Most dual-purpose and off-road four-stroke singles now use some kind of dual-carb system, the theory being that at low rpm, where one large carburetor doesn't mix fuel and air very efficiently, a smaller carburetor will give better throttle response. At increased rpm the secondary carb kicks in to give the engine the fuel it needs for higher speeds. The XT's carbs—a 27mm slide-type primary linked to a 27mm CV-type secondary—are manufactured by Teikei. Most of the time they worked just as the theory dictates, although, there were instances when the engine would stumble, almost as if the secondary carburetor was taking a gulp before getting on with its job. The condition was especially annoying in passing situations on crowded freeways. Before reaching any firm conclusion about the performance of the carburetors, we cleaned and re-oiled the dual-stage foam air filter. This helped—it seems the new XT has inherited the TT600's trait of easily clogged air filters—but a slight hesitation was still there, between 4000 and 5000 rpm.

Hesitation or no, the carburetors metered fuel to the engine very efficiently. On the Cycle World mileage loop the XT returned 61 mpg, giving the bike nearly a 180-mi. range from its 2.9-gal. gas tank. The Yamaha usually went on reserve between 140 and 150 mi.

Carburetion also played a part in the way the big XT started—easily for a 600cc thumper, which is not to say easily compared with most motorcycles. First off, there is no electric starter, since a kick-only design is more in keeping with the bike's off-road, less-weight theme. There is, admittedly, an automatic decompressor that opens the exhaust valves when the kick starter is depressed, but it still takes a healthy kick to get things moving. In the morning it's best to use full choke with no throttle, and the XT will rumble to life in three or four kicks. The bike can be ridden away immediately with the choke still on, since no warm-up period is necessary—a pleasant change from the cold-blooded way many four-cylinder street bikes behave.

When warm, the XT will fire with just one kick .. . usually. There were times—two or three during the 1400-mi. test pe-

riod—that the XT just refused to start. Kicks, curses and push-starting had little effect. After a few minutes rest and some more kicking on the part of the rider, the XT would spring happily into its 1500-rpm idle.

Once started, the engine is a joy. Around town, shifting at 3500 rpm (redline is 7000 rpm) and letting the bike lug its way around corners seems to work best. So with its generous suspension and torquey engine, the XT makes the ideal urban commuter. Potholes, cobblestones and all other normal road hazards don't bother the bike in the least.

Out on the open road, things change a little. Even with the XT's gear-driven counterbalancer and rubber-mounted handlebars, for instance, the rider can feel vibration; this is, after all, a big Single. The vibration doesn't really intrude until the bike is running along at 60 mph, but from that point on the XT shakes in earnest. Not bad for short blasts down the highway, but an Interstate tour at 70 mph will have the rider wishing for something smoother.

Better to stick to two-lane backroads with lots of dips and twists and places to stop and enjoy the scenery. But those stops are almost mandatory, thanks to the hard seat. Thin on top to allow for non-bow-legged standing on the pegs in the dirt, the seat just doesn't offer much support. Fifty miles has the rider shifting his weight around and 100 non-stop miles is a true accomplishment.

Handling-wise, the 600 is nimble in terms of street maneuverability but, naturally, not the most agile dirt bike on the market. But for a bike that can do both kinds of riding, the XT is quite competent. The only handling quirk we did notice was that the bike steers heavily and sluggishly at low speeds. And the culprit is the OEM front tire, a new-pattern Bridgestone Trail Wing. For a dual-purpose tire the Bridgestone has a really aggressive tread design; it would be fair to call the tire a semi-knobby rather than a typical trials-universal dual-purpose design. The tire worked nicely on the street and got surprising traction in the ment we fitted a more conventional Dunlop dual-purpose tire and effected an instant improvement. Even riders who thought that the XT hadn't handled all that heavily with the stock tire noticed a lighter front-end feel with the Dunlop.

Regardless of tire choice, however, the XT makes an excellent off-road explorer. It will splash through streams, climb impressively steep hills and slide around smooth turns at a good clip. On a fire road a talented rider can really hustle the XT along. But, at 318 lb., the bike can become a handful through

rough sections in a hurry. Pushed hard, sooner or later, the weight or lack of real off-road suspension and tires will catch up with the XT; and dumping a heavy bike at the speeds the 600 is capable of is a sobering (and slowing) thought.

Granted, as with any dual-purpose motorcycle, the XT has its limitations both on the street and in the dirt. But that assessment really isn't fair. If you're looking at what a dual-purpose bike won't do well, then you've missed the point. Better to look at what the bike will do; and in the XT600's case, that's just about everything.

Dirt Bike 1984

Yamaha XT600L vss Honda XL600R vs Kawasaki KL600A1

Dual-purpose bikes face a curious dilemma. On one hand, they must be comfortable for long freeway rides out to the country; on the other hand, they have to be nimble in the dirt without feeling too heavy. Yet when you're talking about the biggest engines available in dual-purpose bikes, "nimbleness and lightness" are words usually said in jest.

For this shootout, the Dirt Rider staff compared the Yamaha XT600L, Honda XL600R and Kawasaki KL600A1. They're the biggest, meanest and best dual-purpose bikes we've ever tested.

TECHNICALLY SPEAKING

When Honda's first item on their list of "changes and improvements" for the 1984 bike is "new graphics," you know you'll have to look long and hard for any startling technical information. Actually, the '84 bike is virtually identical to last year's XL600R. The seat height, wheelbase, Ground Clearance, footpeg height and weight are all the same this year, and neither the suspension components nor the tires have changed.

Other than a new shift lever design that now allows for adjustment and a piece of felt soaked in heavy grease above the fork seals to help prevent stiction and lubricate the tube, the only changed items on the 1984 XL600R relate to starting the bike and keeping it from stalling.
First, Honda tossed the old kickstarter and borrowed a less awkWard one from the XR500R. Next, they changed the ignition timing to aid idling.

The carburetors (the same ones as on the XR500R) were also tweaked a bit to help both starting and idling on the monster 600.
Last year, XL600R owners had trouble getting the crankcase drain plug loose while using the Honda-supplied tool kit wrench. Honda has modified the wrench for 1984, so you won't have to dig through the hopelessly inadequate toolbox in your garage.

Tough choice here. Each of the three 600s is loads of fun and possesses characteristics that make it the best in one particular area. The Kawasaki probably has the most potential; its suspension and handling outshine those of its rivals by a fair margin on either street or dirt. However, our test bike was terminally slow and had a comparatively weak front brake, traits that were undoubtedly peculiar to our test bike in talking to some satisfied owners. Also, for a liquid-cooled bike, the engine seemed to get pretty hot, passing the heat back to our legs.

Our Honda was probably the best dirt bike of the bunch. It had a good, strong front brake, handled fairly well and seemed to have the most horsepower, though it was mostly on top. But I didn't like the way it died unpredictably in slow traffic or trail work. It also leaked oil in my garage and the seat was too soft.
By comparison, the Yamaha was great at low speeds:

It would chug down or idle practically all day without a cough and felt stronger down low than the Honda. Its tires seemed better than the ones on the XL or the skinny-feeling ones on the KL. However, it definitely needs stiffer fork springs. Oh yes, the XT is the winner in the clear-mirrors-while-freeway-flying category.
—Mark Kariya

After spending years as a serious racer, dual purpose bikes have won my heart. They are extremely nimble on the street and they are, well ... a lot of fun in the dirt.
Nobody expects a 600cc dirt bike with lights, battery, etc. to handle like a YZ250, but you don't want it to handle like a BMW either. All three of these bikes handle fine on the street, but the Honda feels the closest to a motocross bike once off the highway. Since I'm more concerned with how the bike will perform in the dirt, I'll have to say that the Honda is my choice.

I'd love to be able to say that the Kawasaki is the best, but I can't since the engine doesn't thrill me. A 600cc single-cylinder four-stroke should have so much torque that you can hardly keep the front end down when leaving a stop light. Wheelies on the KL600A1 are more work than they are fun; the engine just isn't as powerful or torquey as the Yamaha and the Honda. feel the same way everybody else on the staff does—put some horsepower in that kWacker and I'd ride it anywhere.
—Bob Carpenter

We took these three bikes out on a head-to-head major trail ride, traveling on freeway sections on the way there and back, and curvy canyon pavement in the middle. We lived with them on a daily basis as commuters and trailsters as well. They are all good for their intended purpose.
I would buy the Kawasaki and hope to find some ponies somewhere. The KL had the best comfort and suspension. I enjoyed it even though it was slow.

The Yamaha has a neat motor and good dirt tires, but the imbalance in the suspension ruins the handling. Passengers were happiest on the rear of the Yamaha. It started and carbureted the best. Honda has been building D-P bikes for a
while, and it shows. Funky carburetion leaves you nervous in traffic, and the Honda's seat is so soft it makes long rides a bummer. Of the three, it does work the best in the dirt and, considering the KL's power, in the street, too.

If you didn't get to ride them all, any one would make you happy. For me, a good dealer would greatly influence my choice.
—Karel Kramer

We took these three bikes out on a head-to-head major trail ride, traveling on freeway sections on the way there and back, and curvy canyon pavement in the middle. We lived with them on a daily basis as commuters and trailsters as well. They are all good for their intended purpose.
I would buy the Kawasaki and hope to find some ponies somewhere. The KL had the best comfort and suspension. I enjoyed it even though it was slow. The Yamaha has a neat motor and good dirt tires, but the imbalance in the suspension ruins the handling. Passengers were happiest on the rear of the Yamaha. It started and carbureted the best. Honda has been building D-P bikes for a
while, and it shows. Funky carburetion leaves you nervous in traffic, and the Honda's seat is so soft it makes long rides a bummer. Of the three, it does work the best in the dirt and, considering the KL's power, in the street, too.
If you didn't get to ride them all, any one would make you happy. For me, a good dealer would greatly influence my choice.
—Karel Kramer

Yamaha's offering in the big-bore department of the dual-purpose world is the XT600L. Compared to last year's XT550K, the 600's new engine displacement was achieved by increasing the bore from 92.0 to 95.0mm, though the same 84.0mm stroke is used on the 600. Yamaha did trim some weight off the piston, the piston pin and other related parts to keep the reciprocating mass equal to the weight of the 550. A larger, three-gallon gas tank is partially covered by the new extended seat. Yamaha says the "safety seat" is for better control in traffic; you know the real reason.

To shave the weight that rides high on the XT600L, Yamaha changed the instrument panel on the new model. Yamaha wanted to lower the amount of weight held up high on the bike. The passenger footpegs are now frame mounted for a more comfortable ride and a new scoop directs cooling air to the cylinder head.
Kawasaki's all-new KL600A1 is a bold new bike, bringing water-cooling to dual-purpose bikes for the first time. Not only is the KL600 water-cooled, it also has a small electric fan to help out when the going gets tough.

The four-stroke engine uses four valves and a double overhead cam. A double rotating counterbalancer cuts down on vibration, and a "silent" cam chain with automatic tensioner helps keep engine noise down. The handlebar-mounted choke makes starting easier, as does the automatic compression release.

ON THE GAS

These dual-purpose bikes are three of the best Open class DP bikes ever built. Each has some quality or personality trait that makes you want to say "Wow!"
The best dirt bike is the Honda. When the pavement ends, the XL600R feels the most like a dirt bike in both body positioning and handling characteristics. It has the shortest wheelbase of the three; that is readily apparent on the trail. Brake slide turns and other motocross-inspired antics were also performed best by the Honda. Both brakes were excellent and never a source of complaint.

Being the best dirt-handling bike doesn't come without sacrifice, though, and in this case, the payoff is substantial. The Honda is the worst street bike of the three. The short wheelbase (55.9 inches) makes the Honda uneasy on the freeway when compared to the Yamaha and the Kawasaki. The passenger pegs on the Honda are mounted on the swingarm, which means every time you hit a bump, your partner's pegs move. If you bottom out the rear suspension, your passenger is going to be very uncomfortable (that's if the pegs didn't already skyrocket your friend).

The engine on the Honda is very strong, but it performs best when revved high. The clutch was never a problem, and all the controls—well, almost all-were usable and durable. After an un-
named Dirt Rider editor tossed the Honda away on a high-speed fire road (he said the corner came up too quickly and he certainly wasn't going to take a ride down a cliff with the Honda) the left-hand rear turn signal was DOA.

The rubber signal ripped off the metal bolt to which it had been molded. But considering the speed of the crash, it wasn't a significant loss.
The best street bike of the bunch is, far and away, the Kawasaki KL600A1. It's stable, handles better than a lot of pure street bikes and the tires let you lean it way over on canyon roads. The seating position and seat (in both shape and density) are the best out of the three bikes tested. Yet the front brake, surprisingly, doesn't feel as strong as the brakes on the other two bikes. It's progressive and positive, but just not all that strong.

In the dirt, the Kawasaki is very predictable and confidence-inspiring. At first glance, you would think the Kawasaki is a lot heavier than either the Honda or the Yamaha. It isn't. On the street or in the dirt, the Kawasaki felt no heavier than the other two bikes.

It was slower, though. Much slower. It could be that we got a lemon for a test bike, but our KL600A1 was decidedly slower than the Honda and the Yamaha, making it hard work staying up with the other two bikes—a pity since the Kawasaki's suspension is much more balanced and of better quality.
We also learned to keep the Kawasaki away from water. After two river crossings and medium-sized sprays, the KL600A1 decided it didn't want to run anymore.

The electrical system died abruptly, and we couldn't get the bike runnin§ again. Since we were in the middle of nowhere, we left the KL in some bushes with additional camouflaging and picked it up the next day. After drying out some, the bike started and ran fine.

The Yamaha XT600L found praise heaped on its chugging motor. It had the best all-around tires, too. The XT was by far the easiest to start. It kicked through easily and fired up after two or three kicks. In comparison, the Honda didn't always want to go when you did, while the Kawasaki needed even more kicks before it could be persuaded to start.
The front fork springs on the Yamaha need to be stiffer to balance out the suspension. While the rear suspension doesn't need to be changed for dirt riding, it was the harshest of the three bikes on the street.

The way the Yamaha handled in the dirt was probably its weakest area. Either because of the unbalanced feel of the suspension or because of the extra weight up high, the XT600L was not exactly a treat to throw into a big, sweeping, fire road corner. You have to get way up over the front end to keep it from washing out, and you can't depend on the rear end to do the same thing every time. High-side swaps were a grim reality during our action photo session. Beyond these complaints, the Yamaha did everything else well. The brakes, the seating position, the controls and the riding comfort are all fine.

So all three bikes have some relatively minor problems, but they've also got some pretty impressive characteristics. They are all excellent dual-purpose bikes, capable of tackling just about any obstacle (speaking from experience), and they are all great on the highway. We'd almost like to call the Kawasaki KL600A1 the winner of our comparison since it handled the best under all conditions and has the best suspension, but it's just too darn slow for a 600cc motorcycle. The Honda could be the winner, too, because-it handles more like a dirt bike (and, after all, we are called Dirt Rider Magazine), but the Honda's seat is uncomfortably soft, and it is hard to start and periodically sputters and dies.