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Yamaha AT1

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Yamaha AT1

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The Yamaha AT1 is a single cylinder enduro motorcycle produced by Yamaha Motor Company from 1969 to 1971.[1] It was part of Yamaha's early efforts to expand their motorcycle lineup and enter the growing off-road market.

Specifications

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Yamaha AT1 Specifications
Attribute Value
Engine 123cc, 2-stroke petrol[1]
Bore × Stroke 56 mm × 50 mm[1]
Top speed 60 mph (97 km/h) plus[1]
Power 11.5 BHP at 7,500 rpm[1]
Torque 8.5 ft-lb at 6,000 rpm[1]
Transmission Wet, multiple disc[1]
Suspension Front: Telescopic fork, Rear: Swinging arm[1]
Brakes Internal expansion[1]
Wheelbase 50.6 in (1,290 mm)[1]
Dimensions L: 77.2 in (1,960 mm)
W: 35.8 in (910 mm)
H: 42.9 in (1,090 mm)[1]
Weight 218 lb (99 kg) (dry)
234 lb (106 kg) (wet)[1]
Fuel capacity 1.9 US gal (7.2 L; 1.6 imp gal)[1]
Fuel consumption 141.1 mpg‑US (1.667 L/100 km; 169.5 mpg‑imp) at 25 mph[1]

Models and Versions

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The Yamaha AT1 was available in three different models, each corresponding to the year of production:[1]

  1. 1969 Yamaha AT1
  2. 1970 Yamaha AT1B
  3. 1971 Yamaha AT1C

Each year, the AT1 was also available in the Motocross edition designated by an M. The M models were very similar to the regular models other than a few performance-enhancing features, such as weight reduction, higher compression ratio, tuned exhaust, larger carburettor with 26 mm throttle bore, and tuned gearing ratio.[1]

Technical Specifications

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Additional Technical Specifications
Specification Value
Compression ratio 7.1:1[1]
Lubrication System Yamaha Autolube[1]
Starting system Electric for Enduro Versions and kick starter[1]
Carburettor VM24SH[1]
Battery 12V 7AH[2]
Ignition system Battery ignition[1]

Model History and Frame Numbers

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Model History and Frame Numbers
Model Year Color Frame Numbers
AT1 1969 Pearl White AT1-100101 to AT1-119829[1]
AT1M 1969 Pearl White (MX Version) AT1-300101 to AT1-303790[1]
AT1B 1970 Competition Yellow AT1-119830 to AT1-144709[1]
AT1C 1971 Competition Yellow AT1-144710 to AT1-170509[1]

Parts and Maintenance

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Some parts, such as fuel tanks, were interchangeable between the AT1 and other Yamaha models of the same era, like the CT1.[3] Yamaha has continued to support these vintage models by producing replacement parts, such as petcocks, which fit the 1969-1971 AT1 models.[4]

References

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  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y "69-71 AT1 125 Specifications". Yamaha Enduros. Retrieved 2024-08-30.
  2. ^ "Yamaha AT1C 125 Enduro Battery Replacement (1969-1971)". Tech Battery Solutions. Retrieved 2024-08-30.
  3. ^ "1969 - 1971 AT1 & CT1 Fuel Tanks Same Size?". Vintage Enduro Discussions. 2021-09-17. Retrieved 2024-08-30.
  4. ^ "Brand New Yamaha Petcocks for our bikes!". Yamaha Enduros. 2014-06-06. Retrieved 2024-08-30.