Four stroke, transverse four cylinder.
DOHC, 2 valves per cylinder.
Capacity
528 cc / 32.2 cu-in
Bore x Stroke
57 X 51.8 mm
Cooling System
Air cooled
Compression Ratio
9.5:1
Induction
4x 28mm Mikuni
carburetors
Ignition
Battery powered inductive
Starting
Electric
Max Power
37
kW / 50PS @
9000 rpm
Max Torque
41.9Nm/ 4,3m-kg@7500 rpm
Transmission
6 Speed
Final Drive
Chain
Front Suspension
Telescopic coil
spring forks
Front Wheel Travel
137 mm / 5.3 in
Rear Suspension
Swinging arm with dual dampers adjustable for preload
Rear Wheel Travel
80 mm / 3.7 in
Front Brakes
2x 267mm discs
Rear Brakes
182mm Drum
Front Tyre
3.25-19
Rear Tyre
110/ 90-16
Wet Weight
205 kg / 450 lbs
Fuel Capacity
15 liters
/ 3.9 US gal
Consumption Average
55 mpg
Standing
¼ Mile
13.4 sec / 98 mph
Top Speed
178.6 km/h / 111 mph
CAN'T AFFORD TO KEEP A 750 IN TYRES AND CHAINS? INTIMIDATED BY THEIR SHEER
_SIZE AND WEIGHT?_ WANT SPEED AND GOOD HANDLING? YAMAHA'S XJ550 WOULD SEEM TO
HAVE IT ALL. DAVE CALDERWOOD REPORTS. PHOTOGRAPHY STEPHEN OLIVER.
I DON'T suppose you've any sympathy for hacks who do most of their
motorcycling on other people's bikes and at other people's expense but it was a
crazy schedule to ask of anyone: Drive 120 miles to Birmingham's NEC for press
day of the motorcycle show in time to catch the»Transport Minister's opening
speech just in case he had anything pro-motorcycling to say for a change. Whizz
round those exhibitors who had their stands complete and time to talk about
new/existing products/plans. Book a couple of road tests with fleet organisers
who'll almost certainly forget the details once back snug in their offices.
Take notes for a Ride On news story (Bike, June '81) and prepare a rough
outline script for a radio interview with Severn Sound later that day. Do radio
interview, hopping from stand to stand and hoping background noise doesn't
overwhelm my rather underwhelming radio voice. Hover around Hesketh stand
waiting for
His Lordship to break off from a (very effective) personal sales campaign.
Get indigestion after scoffing BMW's freebie food at 7,000rpm.
Drive 110 miles back to Herbal Hill where, at 6.30pm, an impatient John
Hunter was waiting with the XJ550 Yamaha which he'd kindly collected for me from
Mitsui earlier that day. Discover that the bike's registration number is
different from the one told to me earlier that week by Mitsui and that my Green
Card insurance was therefore null and void. 'Sod 'em,' said my inner self, now
wound up in my chest like a ball of rusty steel wool.
Return to my flat to gather up gear for the long weekend ride to Le Mans,
France for the early season 24-hour endurance championship round and discover
that my tent was missing. Collect tent from friend five miles away in Black
heath, south-east London, and depart at 8.30pm to catch the 10pm ferry
from Southampton to Le Havre.
'No chance,' said my helpful mate who'd watched me struggling to bungee the
tent onto the pillion seat. 'Gotta try,' said I, refusing to contemplate the
awful hassles which would arise from missing the boat.
Up 'til then, the XJ550 had just been a method of transport, my haste had
blocked out all forms of normal roadtesting analysis but as I swung onto the
south circular road (a popular London joke), the red mist began to clear behind
my eyes and brain activity became a slightly more reasoning process.
Speeding from traffic jam to congested one-way system, the XJ550 proved a bit
of a handful in that at least 6,000rpm was necessary to really get moving; to
maintain constant and readily available urge it was essential to be in the right
one of the six gear ratios. Experienced riders will know that trying to
hard-charge through thick city traffic is stupid and not much quicker than
taking things easy, only using such acceleration as is really necessary and
planning your lane splitting carefully. Later experience on the XJ550 proved
that it's a much more capable town bike than this particular trip was proving.
At last, I poked the front wheel onto the slip road of the M3 motorway and
hit the gas, straight into the outside lane and joining a line of expensive
sleek saloons all clocking a steady ninety per and guaranteed to hide Little Me
from the inquiring eyes of jam sandwiches. Now it was difficult to believe that
the Yamaha was the same bike with which I'd become not a little irritated on the
south circular. It was really flying . . . 90mph . . . lOOmph. Jeez! Was this
really only a 550?
At 10pm precisely, I peeled off the roundabout at the end of the M275
motorway by-passing S'oton city centre and realised it was a hopeless mission,
particularly as I'd seen the fuel gauge's needle dip lower and lower into the
red reserve. Convinced that only a mile or so remained in the float bowls, I
eased the throttle back. The adrenalin rush over, that usual anti-climatic
feeling of a job well cocked-up set in and my riding became sloppy. 'Might as
well wave the others off,' I thought, knowing full well that the rest of Team
Bike ('that anarchic bunch ofliggers. . . ') would forsake alcohol rather than
miss that Thursday night ferry, essential as the correct start to the weekend.
Choosing the wrong dock gate didn't help and by the time — 10.10pm — that I'd
swung through an empty P&O ticket office, a deserted passport control and a
desolate queuing lane I was resigned to a cheapo bed V breakfast and an early
start to squeeze onto the morrow's first boat. So it was with not so much
elation as downright foolhardy euphoria that, as I reached the embarkation
bridge, I could still see the ferry with a juggernaut lorry stuck in its
maw, trying to manoeuvre into an impossibly tight space. Ha! 'Tis the luck o'
the Irish even though I'm not.
Needless to say, the rest of Team Bike, a motley collection of be-leathered
individuals taking up far more than their fair share of bar space, had given me
up. And all they could talk about were damn motorbikes . . .
With such an introduction to testing the XJ550 Yamaha, the rest of my riding
on it might only have been a mere shadow of the real thing if it wasn't for the
fact that it's a real revelation of a mid-weight bike. It's a breakWay from the
super-sanitized Mr Clean and a balls-out sports bike to boot, on the lines of
Yamaha's RD350LC. Comparison with the RD350LC is no accident here; look at the
performance figures and you'll note that the four-cylinder four-stroke XJ550
turned in remarkably similar times as the two-stroke twin RD . . . but a whole
bundle better fuel economy. Two RD350LCs were on this Team Bike trip to Le Mans
so accurate evaluations under similar conditions were possible.
For a start, engine power delivery characteristics are similar — bugger all
below six thou. Hit this threshold though and the next thing you're looking for
is the gearchange as the tacho needle soars up to the 10,000rpm red line. The XJ
would not pull this in top gear at our test track so we settled for a top whack
of 111 mph
with a rider in full leathers and laying prone on the tank. I was sure that
more was to come since the speedo had registered an easy 11l0 mph on the road
(in France, of course) and that was with oversuit, tank bag and tent on board.
Then we checked the speedo accuracy and realised that it was almost illegally
'fast' with an indicated 60mph being a true 55mph. So llOmph indicated was a
true 99mph . . . still not bad.
Having most of the power crowded into the top end of the rev range may make
for a sporty bike but it can often be annoying under regular road conditions.
Stroking the XJ along a typical English A road requires regular use of the
gearchange for manoeuvres such as overtaking down at least two cogs from
sixth — and when confronted with a headwind or steep hill it'll quickly drop off
the boil. Motorway riding, if you're being a good boy for a change, is also
irritating since six thou in top equals 76mph. It's unlikely that you'll be
pulled for that speed but since the inaccurate speedo will be showing about
85mph, you could be worried.
All this high-rev horsepower is the result of a state-of-the-art four
cylinder double overhead cam engine with a modification to the induction system
known to Yamaha engineers as 'Yamaha Induction Control System'. You'll see YICS
stamped on the cam box covers as well as crankcases on most of Yamaha's four
strokes from now on. This isn't an extra gizmo but four extra secondary
interconnected inlet tracts cast into the cylinder head and which join the main
inlet tracts just above each inlet valve seat. As each cylinder starts on its
induction stroke, its secondary inlet port sucks fuel from the other cylinders'
carbs and inlet tracts while their inlet valves are closed. These secondary
inlet tracts are only a quarter of the cross-section of the main tracts so the
air-petrol mixture moves at a much faster rate than the mixture in the main
inlet tract. So when the secondary mix joins the main mix, it gives the whole
caboodle a swirl. This increased velocity and turbulence of the mix improves the
combustion process.
It's not an entirely revolutionary idea since most inlet valves are angled
downwards to create this swirling effect for more efficient cylinder filling and
better combustion but the Yamaha system is claimed to save 10% on fuel.
Certainly our test bike returned surprisingly good mpg considering the thrashing
the bike received. The worst figure was 48mpg and that included the 90-100mph
blat to catch the ferry. The best of 62mpg was clocked when cruising mostly at
an easy 50mph on the return from Le Mans in the company of a dead bike being
towed. Yamaha claim the tank capacity is 3V2 gallons which means that reserve is
just over a gallon. Unfortunately, the fuel gauge needle hits rock bottom far to
early and the most I ever got into the tank was 2.6 gallons — and that was after
riding the last 10 miles into Le Havre and from Southampton to Winchester on
reserve, expecting the bike to conk out any moment. (Question: Why is one of
Britain's major ports surrounded by petrol stations which aren't open at 7am
when the overnight boat docks?)
Though it's a bike which needs to be revved to get the best out of it, it's
not completely useless at low revs providing you don't expect sharp pick-up from
snapping open the throttle. It'll pull smoothly from just above tickover with
none of the cold-bloodedness usually associated with small multis. Choke lever
for the four 28mm Mikunis is mounted on the left bar and operated by the thumb
far better than Yamaha's old method of a push-pull button on the side of the
carb.
Though the bike is close to its XJ650 bigger brother in cubic capacity, it's
miles away not only in 'feel' but there are many engineering differences. The
alternator is mounted behind the cylinders on the 550, as on the 650, but power
is transferred from the crankshaft to the alternator shaft via a Hy-Vo inverted
tooth chain instead of the gears you'll find on the 650. This chain is
automatically tensioned by an hydraulically operated slipper running off engine
oil pressure. A relief valve ensures that excessive oil pressure (such as when
the engine is cold) doesn't over-tighten the chain.
The eight friction plate wet clutch takes its power off the alternator shaft
by straight cut gears and is light to operate though it didn't take our
acceleration tests too well. After five runs, including the 13.48 seconds
elapsed time over the standing quarter-mile quoted, the clutch was dragging
badly and refused to disengage to allow the gearchange from first to second. It
soon cooled off and returned to its normal sweetness and such savage use is
unlikely to be repeated during road use. However, the gearchange was never the
usual slick selection we've come to expect from Japanese boxes and the test bike
may well have been a rogue in this respect.
A single conventional roller chain drives the two overhead cams and there's
only two valves per cylinder, eschewing the complex technology found elsewhere
and normal for the level of power that the XJ produces. Valve clearances are
adjusted by the inverted bucket and shim method.
Rubber engine mounts absorb what little high frequency vibes are produced by
the engine and even at a screamin' ten grand, there's only just a tingle coming
through the 'bars and footrests. There's a black period between four to six
thousand rpm when I suspect there's a hole in the power delivery curve. As
you're going through these revs, the mirrors set up a blur just as you're
checking to see whether hyper-speed is safe to move into. By the time they clear
again, you're already committed.
What really makes the XJ550 such a sports bike, apart from its power, is the
light overall weight — 4101b dry though that's only just less than a Bonneville
(watch it Dave, no jingoism here please). Like the RD350LC, the XJ has that
twitchy feel to the steering that comes with a fairly short wheelbase of 55
inches and which reacts quickly to both rider and road inputs. I like that light
steering feel which makes a mid-weight bike so chuckable and the XJ's excellent
weight versus bulk balance encourages this. It's one of those bikes that you can
enter a series of your favourite bends at a very interesting speed, feel the
tyres begin to skip, ease the angle of lean and change lines, all without the
anxiety that the same manoeuvre would induce on a 750 or lOOOcc bike. And that's
with the standard tyres which just have to be the worst Bridgestone have
produced in yonks. At the front is a ribbed Mag Mopus which is okay, but nothing
special, as deserved by a bike of this nature. The rear tyre is a throwback from
the days of Jap tyres when they were best used by Thames barges as fenders.
Admittedly it had worn to a flattish profile in the centre but it was still well
within the legal limits, and overall mileage on the bike was only 2500 miles at
this stage.
So good and controllable is the XJ550's handling that this deficiency in the
roadholding department was only a problem during the peel-off moment when
entering a bend fast. Neither are the rear shock absorbers much cop. Suspension
front and rear is surprisingly non-high tech considering the XJ's main rival
will be Kawasaki's GPz550 which has air assisted forks and adjustable damping at
the rear. The Yamaha's forks don't suffer at all by being 'only' coil spring and
work exceptionally well, but the rear shocks had to be put on maximum spring
preload to maintain ride height. That was with just me, an 11-stone weed, on
board — with a pillion it was just a joke. The rear shocks were so bad that I'm
beginning to think that somewhere along that bike's preparation line, the wrong
pair were put on. Maybe there's an RS100 somewhere that's vastly oversprung.
That twitchy feel I mentioned earlier could well be tamed, and the whole
bike's roadholding transformed, with a decent set of tyres and rear shox — the
same old Japanese bike complaint we were making years ago! There's no worry over
the brakes though. In wet or dry, the twin front discs are incredibly powerful
yet also progressive and are well matched by the rear single-leading-shoe drum
brake, rod-operated. At the test track, it was impressive to try emergency
braking which could be controlled finely — nothing like the dead 'feel' you
often get with the now common metallic disc pads. With each new Jap bike we seem
to get completely redesigned brakes but these latest floating calipers on the XJ
are as good as Brembo's latest twin piston type. Mind you, the Italians did get
it right an awful long time before the Japs.
The road to Le Mans after leaving behind Le
Havre's oil refineries is definitely in the ace roadtesting league. It's got
a heady mixture of tight, abrasively surfaced bends over an undulating
landscape, many series of twists up 'n' down dale that you can see all the way
through and plan a racing line with no fear of adding a dash of red to the
Normandy countryside's idyllic green hue, and all this is followed by long
straights into the urban street racing circuit around the environs of Le Mans.
It was along such roads that I came to the conclusions about the XJ's
suspension but also discovered that it didn't really matter anyway since the
bike was so much fun. Part of this rider control is the excellent
footrest/seat/handlebar relationship which leans you forward just so.
Footrests on the XJ are well to the rear and quite high so your knees are
severely bent. This attitude pushes you forward onto the 'bars which are hardly
raised at all from the level. Levers, pedals, switches, instruments, etc all
fall easily to fingers/feet/tnumbs/eyes.
While the riding position is great for a sporty solo rider, it's a bit of a
tight fit two-up, especially if you're trying to squeeze on luggage somewhere
too. The rearset footrests that make for one-up total control also mean you and
your passenger's feet entangle occasionally. It's not that two-up trips are an
impossibility, just that here's a bike that gives its best ridden hard; if
you're into touring with a friend, forget the XJ. It was a tight fit too for me,
a lanky six-footer with size eleven boots, with just a modicum of luggage — tank
bag, tent and, on the return journey, a stuffa bag.
In fact, the return trip from Le Mans wasn't so enjoyable as the trip down
though it was certainly memorable, even allowing for the heavy heads among our
party. Roads made greasy from light rain, then awash in sudden cloudbursts,
showed up the XJ's skittishness and lack of surefooted roadholding. Again, its
relative light weight made control of steering no problem but once or twice, I
accidentally locked up the brakes. Back on home soil, after eventually filling
up at Winchester, the blast back up the A33 and M3 to London was straight into a
strong headwind which cut the top whack of the XJ down to around 90mph — and an
RD350LC alongside was similarly reduced. It wasn't a lack of power but just too
much wind force on the rider's neck and upper arms. I'm sure that if either of
us had been alone, we'd have done the sensible thing and settled for an easier
ride at 70mph.
All the usual Jap equipment is quite adequate: headlamp is a 50 Watt main
beam/40 Watt dip unit with reasonable penetration into the murk. Self-cancelling
indicators are standard as are the Mockett italic cast wheels. Twin horns
mounted below the headlamp rather spoil the front view but have a surprisingly
loud noise. Toolkit is the usual joke. My only other major criticism is how hard
it is to clean the engine thoroughly. Crankcases, barrels, heads and alternator
cover are all matt black which may be correct from a heat dissipation viewpoint
but hell to keep free of crud. The oil cooler mounted just underneath the
steering head and with plumbing in between front down tubes, collects grubbiness
too.
So many motorcycles of all capacities, shapes and sizes are available today
and each category is incredibly competitive, especially among the Japanese
offerings. The XJ550 Yamaha is in the same mould as Honda's famous 400cc four
but with all the improvements in motorcycle technology that have taken place
since then. It's not the stuff that legends are made of — such as the RD350LC —
but then who wants to be a broke folk hero anyway?