Yamaha XS1100SF Midnight Special (1981)

The Yamaha XS1100SF Midnight Special motorcycle was introduced in 1981 and featured a four-stroke transverse four-cylinder engine with a capacity of 1101 cc. It had a compression ratio of 9.2:1 and was air-cooled. The bike had a maximum power output of 95 hp at 8500 rpm and maximum torque of 9.2 kgf-m at 6500 rpm. The ignition was TCI with an additional vacuum adjustment, and the bike had an electric kick starter that was separate from the engine and only for emergency use.

The XS1100SF had a wet sump lubrication system and was equipped with a wet, multi-disc clutch and a five-speed transmission. Its primary reduction system was HY-VO chain and gear with a primary reduction ratio of 1.657. The final drive was a shaft, and the bike featured five gear ratios.

The front suspension of the XS1100SF was a telescopic fork with a front wheel travel of 175 mm, while the rear suspension was dual shocks with a swing arm that was preload adjustable and had a rear wheel travel of 80 mm. The bike had front and rear disc brakes, with a front tire size of 3.50-19 and a rear tire size of 130/90-16.

The XS1100SF had a wet weight of 258 kg and a fuel capacity of 15 liters, with an average fuel consumption of 40.3 mpg. Its braking distance from 100 to 0 km/h was 39.7 m, and it could achieve a standing quarter-mile time of 11.7 seconds at 114.2 mph. The bike had a top speed of 126 mph.

Technical specifications:

Make Model: Yamaha XS 1100LH Midnight Special

Year: 1981
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: 130/90 -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