1937-1965 Ariel Workshop Manual: Square Four, Leader, Arrow & Twins / Singles
Troubleshooting, parts diagrams, and service data for Square Four 4G, Leader, Arrow, KG/KH/FH Twins, and single-cylinder models. Complete overhaul procedures, ignition timing, and carburetor adjustment specifications.
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Sample pages from the 1937-1965 Ariel Workshop Manual: Square Four, Leader, Arrow & Twins / Singles manual
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Ariel Models Covered & Key Technical Specifications
Models: Ariel Square Four (4G models), 250cc Twins (Leader, Arrow), 500cc Twins (KG, KH, KHA, FH, Fieldmaster, Red Hunter, Huntmaster), 200cc Single-cylinder (Colt), 250cc, 350cc, 500cc, 600cc Singles (OH, LH, NH, OG, LG, NG, WING, VG, VM, VB, Hunter, Red Hunter)
Sub-models / Variants: 4G Mk I, 4G Mk II, Leader, Arrow, Colt, Red Hunter, Fieldmaster, Huntmaster
Trade Names: Square Four, Leader, Arrow, Colt
Build Years: 1937–1965
Technical Data:
- Engine displacement: 1,000 cc (Square Four 4G), 200–650 cc (Twins and Singles)
- Carburetor type: S.U. Type M.C.2, Amal
- Electrical components: Lucas equipment (Magneto, Dynamo, Wipac alternator)
- Lubrication system: Oil sump capacity 2.8 liters (0.74 US gallons)
- Ignition timing: 28–32 degrees BTDC specified for select models
- Engine speed: Calibrated to 6,500 rpm maximum performance threshold
- Operating temperature: 65–85°C (149–185°F) thermal envelope
Ariel Manual Features & Content Preview
Ariel 1937–1965 Workshop Documentation
- Covers 1937–1965 Ariel Square Four 4G, Leader, Arrow, and various twin/single-cylinder motorcycle variants including the 200cc Colt
- Official Ariel workshop publication, Sixth Edition, published by C. Arthur Pearson Limited
- Contains 84 detailed drawings and exploded-view diagrams depicting internal engine, transmission, and chassis assemblies
- Stored against your account so you can retrieve it after a hard-drive loss
- Full-text search finds any part number in seconds
- This 1937–1965 edition serves as the definitive reference for the transition from the 4G push-rod engine through the later Leader and Arrow twin-cylinder production years
Factory Service Scope
The 1937–1965 Ariel workshop manual details maintenance and overhaul procedures for the complete Ariel motorcycle range. Chapters delineate the 1,000cc 4G Square Four engine developments, including the Mk I and Mk II transitions and the introduction of S.U. Type M.C.2 carburetors. Dedicated sections document the 250cc Leader and Arrow twin-cylinder designs, alongside the comprehensive line of 200cc to 600cc single-cylinder models such as the NH, VH, and Red Hunter.
Additional chapters provide data for the electrical systems featuring Lucas components, including magnetos and dynamos, as well as complex front fork and steering assembly maintenance. The document further catalogues rigid and plunger-type frame details, chain adjustments, and wheel hub servicing. Learn how factory workshop documentation is structured to assist in identifying component specifications across the diverse Ariel lineup.
Technical Specifications Preview
The manual provides essential clearance settings and torque values for engine and transmission teardowns. Specific lubrication recommendations for both the 1,000cc Square Four and the various 250cc to 650cc models are indexed for efficient reference. Intake valve clearance for the Square Four is listed at 0.003–0.004 inches in the technical data tables. The oil sump capacity for the engine is documented at 2.8 liters. Crankshaft rotation for maximum performance is calibrated at 6,500 rpm. Note: This page is a contents overview for the manual. It does not provide repair or diagnostic instructions. An authentic 119-page Ariel OEM factory manual documenting the 1937–1965 period, providing comprehensive technical specifications and exploded-view diagrams for the Square Four, Leader, Arrow, and the complete series of vintage single and twin-cylinder models.
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