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Yamaha XJ 550R Seca

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Make Model

Yamaha XJ 550R Sega

Year

1981

Engine

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 / 50 PS @ 9000 rpm

Max Torque

41.9 Nm / 4,3 m-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

Labels arerelative.Though the Seca hasn't changed mechanically, it's drifted from sport to mainstream— in comparison, of course, to the competition.
Superbikes with their claim to 11-second quarter-miles and outrageous top speeds—dominated the Seventies. In a similar way, middleweights are laying claim to the Eighties. Capable of mid-twelves in the quarter, with agility unrivaled by full-liter bikes and, maybe best of all, carrying price tags well below three grand, the best of the 550s are attracting sport enthusiasts like never before.
Kawasaki opened up the '80s with the introduction of the KZ550—faster than any of the other middleweights except Yamaha's 650 Maxim.

The KZ's only class rivals (the Honda 550-turned-650 and the Suzuki 550) were mildewing with age, designed in the early- to mid-'70s with only minor subsequent updates.
So along came 1981, and Yamaha sprang the Seca on us, which was competitive with Kawasaki's refined KZ and new GPz. But technology (thankfully) keeps blossoming: the GPz got better in 1982 while the Seca dropped back a notch. Still, the Yamaha ranked above the musty
Honda and Suzuki middleweights.
Nineteen-eighty-three — and, oh what a difference a year makes! The Kawasaki GPz has been refined, Suzuki's 550 is all new (with racetrack-inspired styling and technology), and Honda's new Nighthawk 550 and 650 are fast, fast, fast. And the Yamaha Seca? It is, basically, an '81 bike with more sedate styling. Less its handlebar-mounted sport fairing and flashy red-on-white paint scheme, the new Seca comes only in black with red and purple stripes. Following an '82 change, the front fender and fork sliders are color-matched to the bodywork.

This latest Seca has more mainstream appeal, though its sporting potential is still commendable. Moreover, it remains the lightest and narrowest four-cylinder bike in its class.
Mechanically, the Seca is unchanged from the original model. The narrow engine design, made possible by mounting the alternator on top of the transmission case, was an important step in creating a more compact, lighter motorcycle. Honda is just now using that design on the new Night-hawks. Narrow engine cases do more than just improve Ground Clearance; ergonomics improve as well. With a narrower engine, the footrests can move in closer to the fore-aft center line of the motorcycle.This enables the pegs to be mounted low, allowing a fairly expansive seating position while still maintaining good cornering clearance.

Though modern in design, the Seca's twin-valve double-overhead-cam engine lacks the development of other manufacturers' mid-sized fours. Quarter-mile performance strongly reflects an engine's output, and here the Seca falls behind. Its quarter-mile figures—13.05 @ 98.46—pale against those of the current 550 King, the GPz.
Kawasaki's rocket will blast through the quarter in 12.7 seconds at 103 miles per hour, while offering the same versatile power as the Yamaha.

The Seca uses a straightforward chassis design. With 27 degrees of rake, 4.29 inches of trail and a 55.5-inch wheelbase, the 550 promises a cross between agile and stable handling, and it makes good on that promise. The Seca staggers very little in crosswinds, and the bike does nothing to surprise the rider; it just plain works well. Though its suspension components lack air assists and adjustable damping, the Seca accommodates most riding styles and handles most conditions well—exactly as a mainstream motorcycle should.

The Seca's seating position falls between traditional and sport. The handlebar's pullback invites an upright riding position, and, fortunately, the instrument nacelle is high enough to act as a decent windbreak; the traditional-style handlebar won't cause wind-related discomfort unless you regularly cruise at supra-legal speeds. The footpegs, mounted halfway between sport and traditional, complement the seat-bar position well. A comfortable seat allows easy cruising for an hour or all day; the short step leading to the passenger area is small enough to let tall solo riders scoot back easily.
History seems to be repeating itself, with just a change in characters. A few years ago the Yamaha Seca was the fresh face in the crowd of middle-weights while the Honda and Suzuki were the tried-and-true standbys. For 1983 the roles are reversed: the Seca has established itself as a solid performer by providing good power and handling all around (but not the best in class), while the new bikes are waiting in the wings to prove themselves.

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