* It came in one color: Monza Red
* The gas tank, side covers, fenders, headlight cowl, and frame were red
* The seat, fork boots, number plate panels, and engine were black
* The wheels, fork legs, and swingarm were silver
* The "600R" side cover decal was solid white
* The engine was a 589cc OHC RFVC single cylinder with two carburetors and two
head pipes
* The transmission was a 5-speed.
* Engine: RFVC radial valve, 589cc dual-carburetor dry sump
* Transmission: 5-speed
* Suspension: Pro-LinkTM rear suspension
* Brake: Disc front brake
* Wheelbase: 1420mm (55.9 in.)
* Dry weight: 134 kg (295.3 lb)
* Seat height: 860mm (33.8 in.)
* Front wheel travel: 229mm (9 in.)
* Rear wheel travel: 203mm (8 in.)
* Tank, side covers, fenders, headlight cowl, and frame are red
* Seat, Fork boots, number plate panels, and engine are black
* Wheels, fork legs, and swingarms are silver
* "600R" side cover decal is solid white
* V.I.N.: JH2PD0301DM000027
* Engine serial number: PD03E-5000053
Bicycle tracks. Our guest in the wilds of Mexico was puzzled. He'd been first
away from the gas stop and had pushed his open class enduro bike at a good pace
across the ranchlands and into the foothills. There'd been rain the previous
day, so the two-rut road wasn't marked. Except that he was following some odd
tracks. Obviously a two-wheeler of some sort, but instead of the normal knobby
marks the tracks were narrow, nibbly, almost delicate. All he could think was
that somehow he was trailing a bicycle.
The ride led onto a stretch of pavement, then a challenging sand wash. Into a
small village, onto another dirt road ... and there were those bicycle tracks
again. He followed them into another village, up to the local gas pump and
there, its rider halfway through his second sandwich, was Honda's new XL600,
skinny trials tires and all. That's the truth.
It's not the whole truth; given the usual dirt trails and fire roads, the
XL600 isn't a match for a big enduro, or any true dirt bike regardless of engine
size.
This ride wasn't a purist ride. Instead, it began at the edge of town, on
pavement. The true enduros had to gas it and coast on the straights; can't
cruise a racing two-stroke. And careful on the corners with those knobs.
But the XL600 could cruise at 75, while the universal tires held on nearly as
well as road tires and gave advance warning when pushed to the limit. So the XL
was first to the gas stop.
Except, being a stingy four-stroke, it didn't need gas. So it was first to
the next pavement section, where it gained ground again.
Our man somehow missed (Ha! —ed.) the sand-wash and kept on the dirt road.
And so it went for 300 mi. and two days of serious trail riding, during no part
of which was the XL600 out of the first five.
Why on earth can't we come up with a suitable name for such machines? Dual
Purpose? Humbug. This is neither an underweight road bike nor an overburdened
dirt bike.
The XL600 is an excellent motorcycle, limited by its name, and a couple of
physical facts.
The components are mostly familiar. Honda believes in these machines, so
along with the XR350 and XR500, the new family of four-stroke Singles includes
the 600, by the simple trick of giving the 500 a larger bore, 100mm instead of
92.
This was done because meeting road-legal requirements for exhaust noise and
emissions, and the extra weight that's also part of the street package, reduces
power and power-to-weight. The XL600 is in a softer state of tune, with lower
compression ratio and bigger muffler, but by increasing displacement the 600
gets a claimed output of 43 bhp, compared with the XR500's 41.
Honda designers obviously prefer results to sales pitches. Remember the
complicated, power-robbing counter balancers not fitted to the VT500 V-Twin? The
XL600 has one. When the second generation XLs came out, the company said they
had open-loop frames and wet sumps to lower the engine. The XL600 has a full
cradle frame and dry sump, to lower the engine. And we won't even mention the
21-in. front wheel replacing the 23-incher.
Along with the really new (and effective) developments like the radial valve
head and compound carbs, the XL600 has a feature that's new and unique: A
decompression chamber.
Survivors of pre-Honda Big Singles know all about kicking (and being kicked
by) 500-plus Singles. All the modern engines in class have some form of
compression release linked to the valve gear, usually activated by the kick
lever.
The 600 has a compression release, but it's worked by the left hand. The kick
lever activates a fifth—yes!—valve, a tiny one packed into the combustion
chamber with the other four and the spark plug. This valve leads to a cavity
formed in the left rear of the cylinder head's exterior, and capped with a
bolt-on cover.
This is really new. This chamber has the same volume as the combustion
chamber. The little valve opens on the compression stroke. It doubles the space
into which the charge is being compressed, hence the compression ratio is half
what it is when the engine is running. And this means the engine is only half as
resistant to being kicked through. Remarkable device.
The XL600 engine and XR500 engine are shorter (by 2 in.) in length and
shorter (by 1 in.) in height and 0.2 in. narrower than the old 500 Singles.
Compact is the word here, as the new ones are 5 lb. heavier than the old.
The big XL and XR also share the new frame, with chrome-moly steel for the
tubes which hold the engine oil, mild steel for the rest. The XL has the dual
piston single front disc brake, the Pro-Link rear suspension, 39mm Showa forks,
all the XR stuff, right down to a skid plate and quick-release rear hub. The
rear suspension has four settings for rebound damping and a useful range of
spring pre-load. Wheel travel, naturally, is less than the XR's while the road-goer
weighs more, so the springs are stiffer. The headlight has a halogen bulb,
bright enough for the highway even though the light and its numberplate-like
housing look too racy to be practical.

Now, the various pros and cons.
First, pros:
This thing is fast. We are so used to moaning about weight in
the four-stroke playbike class we forget there's weight and there's weight. At
315 lb. the XL is a bulky dirt bike. But 315 lb. is light for a 43-bhp
motorcycle.
The XL turns performance figures comparable to several Twins. A quarter mile
in the high 13s is no slouch; this time we don't have to mention that it's
quicker than the average $50,000 car. This is a quick time on two wheels. And
the XL is a genuine 100-mph bike. (It does develop a gentle weave over the ton,
by the way, to the point of alertness instead of fear, and because the wheelbase
and steering head angle need to deal with trails and berms unknown to ordinary
100-mph machines, it's no big deal.)
The short (for the street) wheelbase and high center of gravity should hamper
acceleration and braking, but they don't. Slip the clutch off the line, lean
back and don't bother with the rear brake on full-hard stops, no problem. Nor
should we forget 61 mpg, either.
The gearing was picked for the engine's power, not the supposed class of
motorcycle. Again, 4200 rpm at 60 mph is the sort of cruising speed one expects
from Twins and multis. The XL uses the same transmission gear ratios as the
XR500, but has a higher primary gear and higher final drive, the better to work
on the highway.
The real bonus here is that repli-numberplate. It's a real wind-breaker.
There you sit, straight up on the tall saddle, arms out to the enduro-spaced
grips and darned if you aren't comfy. The plate lifts the blast just enough to
make 60 an all-day speed, with 75 live-able when other, ahem, conditions are
right. Sure, at 100 you're tucked in or your helmet's halfway flattened your
nose, but 100 is something for rare occasions. And the gearing, again, lets all
this work. Oh, so does the counter balancer. The 600 is as smooth as the average
Twin. (And while we're at it, the gear ratio in 5th is 0.840:1. The engineers
snuck this past the sales office before they could inflict another OD light on
us. Don't tell, okay?)
The serious points against the XL aren't so much con as they are the debit
side of the compromises all designs require.
Because the 600 is so strong and can provide so much speed without being
buzzed, the gearing is tall all the way up. The XL is nearly impossible to ride
smoothly at less than 40 mph in top. There isn't much flywheel effect and the
engine thumps, just like they say in the history books. These bangs are
delivered in the form of chain snatch and wheel judder. Shift down and it's
gone. But the even pulse of a big Single does have a charm lacking in this
example.
Next, the engine can be pure king hell to start.
This is science versus raw nature. There's some sort of law that says there's
a practical maximum for the bore of a cylinder, in a motorcycle, or car. That
maximum is about 100mm.
The bore of the XL600 is 100mm. So, while we have the decompression chamber,
and compound carbs so there's good air flow at low speed and at kick-over speed,
and the latest in electronic ignition, we still have that vast bore across which
the flame front must advance, and above which the mixture must stay mixed.
As an extra handicap, the spark would be stronger if the ignition drew on the
battery instead of the alternator for its power source. But that means depending
on a battery, not always a good idea on a dirt bike. Our first test XL600
fractured its battery after 300 mi. of hard, rough riding. Still ran, still had
lights and all that, and we were glad not to need the battery, so we vote for
the factory's way.
But.
The XL600 will fire in a few kicks, from cold. It will fire with a few kicks,
when hot.
In between, it can be a pig. Lukewarm means it will flood on full choke, but
won't mix right with no choke and no human being can tell just where in between
is right. Warm-up takes at least a mile, sometimes two or three. Short hops thus
become a gamble, and that means the bike isn't quite as handy as it would
otherwise be.
Oh, and the engine sometimes kicks back. Hard. Hard enough to bruise your
foot through your stout boots. Our first one kicked back. We were so impressed
with the XL that we broke our rules and went riding before we had pictures,
resulting in a machine too scuffed to photograph. So we borrowed another. It
kicked back. And we know a private owner. Kick back? we asked. Ouch, he said.
Ease the engine past TDC, just like in the old days, is our advice. And keep
your knee bent.
Several of the styling features interfere with what the XL600 is supposed to
do. The sales departments of the world have learned that enduro bikes sell best
if they resemble motocross bikes. So they figure it follows that a dual-purpose
bike should look like an enduro bike, which the XL600 does, with its low,
narrow, flat seat, short and peaked fuel tank and abruptly bobbed rear fender.
Except that the short peaked tank rules out a tank bag. The thin, narrow and
square seat is fine in motocross or enduro because you don't sit on it, you
pivot around on it. For a sit-down bike, which the XL should be, it's a pain.
Nor is there enough room for a passenger for more than a mile or so, nor can you
use even the smallest of saddle bags or strap-on soft bags. Impractical is too
strong. More like less practical for day trips, which should be the XL's
strongest point.
Tires don't merit criticism. They're trials universal, suitable for dirt or
pavement, not the best for either but that comes with the class. And the
Bridgestone Trail Wings are as good as any. So. With the XL600 we have a
triple-purpose motorcycle: City bike. It's light and quick and steers and stops
and because it responds instantly to any and all commands, it's good in daily
use. But not any better than good, not with there being no provision for
briefcase, homework, lunch pail, the day's groceries. Subtract extra points for
the hazards of having the engine quit and get temperamental.
Dirt bike. Better than the above. The suspension has plenty of travel, some
scope for adjustment. Power is obviously no problem at all. The limits are
dictated by the tires. They don't grip like knobbies in sand or mud and the
narrow front tire will knife through sand, mud or any loose cover while the rear
tread packs or spins. The answer is to pick your territory. On graded dirt or
gravel or hard pack, the XL won't give much away ... when ridden using momentum.
The front won't stick, and the bike can't be banked off the berm or wrestled
between the trees. The back won't hook up and rocket you away. But the XL will
work fine if treated with respect. Coast in, feather out, make no sudden moves.
Momentum. And when the track is straight, gas it. The rider, and the others in
the party, will be surprised and impressed at how quickly this bike will cover
the unpaved ground.
Explorer bike. Here we go. Dual-purpose motorcycles have suffered from
inattention for several years, ever since research showed the average example
spends 80 percent of its time on pavement, 20 percent off road. This seemed to
prove some sort of lack, a strong hint that the bikes (or their riders) weren't
really doing it right.
What wasn't done right was the research. These people were counting calories,
so to speak. Dinner at the snack bar in the bus depot equals 2000 calories,
dinner your mom cooks when you get home equals 2000 calories, therefore dinner
in the depot equals dinner by mom.
Obviously, it doesn't.
What we have here is a motorcycle with the lure of high performance, hampered
by the stigma of low cost.
Those who can overcome their need for back-up trucks and tune-ups by
factory-trained mechanics only, who can ride dirt with craft and skill instead
of letting the bike spare them the penalty for their mistakes, will be rewarded
by the XL600.
Source Cycle World 1983