Yamaha XS1100SF Special (1979)

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The Yamaha XS1100SF Special is a four-stroke transverse four-cylinder motorcycle produced in 1979. It has a four-valve per cylinder and an air-cooled engine with a 1101cc capacity. The bike has a compression ratio of 9.2:1 and uses a 4x Mikuni BS 34SS Carburettor induction system.

The XS1100SF Special has a wet sump lubrication system, a TCI ignition, and uses a BP6ES (NGK) or N-8Y (Champion) spark plug. The motorcycle also features a GM 18Z-3A / 12v, 20 AH battery and an AC generator with a voltage regulator and rectifier.

The XS1100SF Special has a maximum power of 95 hp / 70.8 kW @ 8500 rpm and a max torque of 9.2 kgf-m / 66.5 lb-ft @ 6500 rpm. It uses a 5 speed transmission and a shaft final drive. The motorcycle also features telescopic fork front suspension and preload adjustable dual shocks swing arm rear suspension.

The XS1100SF Special has front and rear disc brakes with a wet weight of 258 kg / 568.7 lbs. It has a fuel capacity of 15 Litres / 3.9 US gal and consumes an average of 40.3 mpg. The motorcycle has a top speed of 126 mph / 202.8 km/h and can brake 100-0 in 39.7 m, completing a standing quarter-mile in 11.7 seconds at a speed of 114.2 mph / 183.8 km/h.

Technical specifications:

Make Model: Yamaha XS 1100SF Special

Year: 1979


Engine: Four stroke transverse four cylinder, DOHC, 2 valves per cylinder.
Capacity: 1101 cc / 67.2 cu-in
Bore x Stroke: 71.5 x 68.6 mm
Cooling System: Air cooled
Compression Ratio: 9.2:1
Induction: 4x Mikuni BS 34SS Carburettor
Lubrication: Wet sump
Ignition: TCI additional vacuum adjusted! / electric kick starter – Witch is separated from the engine, for emergency mounting only
Spark Plug: BP6ES (NGK) or N-8Y (Champion)
Battery: GM 18Z-3A / 12v, 20 AH
Generator: A.C. Generator, voltage regulator, rectifier
Starting: Electric
Max Power: 95 hp / 70.8 kW @ 8500 rpm
Max Torque: 9.2 kgf-m / 66.5 lb-ft @ 6500 rpm
Clutch: Wet, multi-disc (8 drive plates, 7 driven plates)

Transmission: 5 Speed
Primary Reduction System: HY-VO chain & gear
Primary Reduction Ratio: 25/25 x 58/35 = 1.657
Final Drive: Shaft
Gear Ratio: 1st 38/17 (2.235) 2nd 39/24 (1.625) 3rd 36/28 (1.286) 4th 32/31 (1.032) 5th 30/34 (0.882)
Front Suspension: Telescopic fork.
Front Wheel Travel: 175 mm / 6.8 in
Rear Suspension: Dual shocks Swing arm, preload adjustable
Rear Wheel Travel: 80 mm / 3.1 in
Front Brakes: 2x 298mm discs
Rear Brakes: Single 298mm disc
Front Tyre: 3.50-19
Rear Tyre: 4.50-16
Rake: 29 o 30
Trail: 130 mm / 5.1 in
Wet Weight: 258 kg / 568.7 lbs
Fuel Capacity: 15 Litres / 3.9 US gal
Consumption Average: 40.3 mpg
Braking 100 – 0: 39.7 m
Standing 1/4 Mile: 11.7 sec / 114.2 mph 183.8 km/h

Top Speed: 126 mph / 202.8 km/h

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