Yamaha DT125 (1981)

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The Yamaha DT125MX is a 1981 motorcycle with a two-stroke, single cylinder engine featuring reed valves. It has a 123cc capacity, and a compression ratio of 7.2:1. The lubrication is provided by Autolube, and it has a 0.9-litre oil capacity. Induction is via a single 24mm Mikuni carburettor, and ignition is through a flywheel magneto. The starting mechanism is kick-start only. The motorcycle can generate up to 14 horsepower at 6,500 RPM, and has a maximum torque of 1.5 kgf-m or 15.2 Nm at the same RPM. The clutch is multiplate and wet, with six-speed transmission and a chain final drive. The front suspension comprises telescopic forks and offers a wheel travel of 160mm. The rear suspension consists of a monocross unit, giving a wheel travel of 115 mm. The bike has drum brakes on the front and rear wheels, with tyre sizes of 2.75-21 and 3.50-18. The dimensions of the Yamaha DT125MX are 2080mm x 885mm x 1120 mm, with a wheelbase of 1325 mm and seat height of 855 mm. The ground clearance is 265 mm, and it has a dry weight of 96 kg. The fuel capacity is 7 litres, with an average consumption of 79 mpg. In terms of speed, the bike can reach a top speed of 74 mph and complete a standing 1/4 mile in 19.9 seconds.

Technical specifications:

Make Model: Yamaha DT 125MX

Year: 1981


Engine: Two stroke, single cylinder, reed-valve
Capacity: 123 cc / 7.5 cu-in
Bore x Stroke: 56 50 mm
Cooling System: Air cooled
Compression Ratio: 7.2:1
Lubrication: Autolube
Oil Capacity: 0.9 Litres
Induction: Single 24 mm Mikuni
Ignition: Flywheel Magneto
Starting: Kick
Max Power: 14 hp / 10.3 kW @ 6500 rpm
Max Torque: 1.5 kgf-m / 15.2 Nm @ 6500 rpm
Clutch: Wet multiplate
Transmission: 6 speed
Final Drive: Chain

Front Suspension: Telescopic Forks
Front Wheel Travel: 160 mm / 6.2 in
Rear Suspension: Monocross
Rear Wheel Travel: 115 mm / 4.5 in
Front Brakes: Drum
Rear Brakes: Drum
Front Tyre: 2.75-21
Rear Tyre: 3.50-18
Dimensions: Length 2080 mm / 81.8 in Width 885 mm / 34.8 in Height 1120 mm / 41.0 in
Wheelbase: 1325 mm / 52.2 in
Seat Height: 855 mm / 33.6 in
Ground Clearance: 265 mm / 10.4 in
Dry Weight: 96 kg / 212 lbs
Fuel Capacity: 7 Litres / 1.58 gal
Consumption Average: 79 mpg
Standing 1/4 Mile: 19.9 sec
Top Speed: 74 mph

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