Ariel Workshop Manual for Square Four, Leader, Arrow, Twin and Single Cylinder Motor Cycles 1937-1965

Restore Your Classic Ariel: The Ultimate 1937-1965 Workshop Manual

Own a piece of British motorcycling history? Whether you are wrenching on a legendary "Squariel" or a nimble Arrow, this comprehensive Workshop Manual by C.W. Waller, Ariel's own Factory Service Manager, is the definitive resource for every owner, restorer, and mechanic. This sixth edition provides technically accurate data and step-by-step instructions to keep your vintage machine on the road.

Complete Model Coverage (1937-1965)

This manual deals with the full spectrum of Ariel engineering, from the pre-war era through the mid-sixties:

• The Square Fours: Complete 1,000 c.c. 4G models. Includes the early cast-iron units and the redesigned 4G Mk. I (light-alloy block) and Mk. II (four-pipe exhaust/high compression).
• The Twins: 250 c.c. (Leader and Arrow), as well as the 500 c.c. and 650 c.c. powerhouse models (KG, KH, KHA, FH, Fieldmaster, Red Hunter, and Huntmaster).
• The Singles: A vast range including the 200 c.c. Colt (LH model) and the 250 c.c. to 600 c.c. OHV and SV Singles (OH, LH, NH, OG, LG, NG, WNG, VG, VM, VB, Hunter, and Red Hunter).

Expert Technical Guidance

Written by a factory expert, this guide moves beyond basic overviews to provide deep-dive technical procedures. It features 84 detailed drawings and photographs to help you visualize complex assemblies like the 1,000 c.c. lubrication system and timing gear layouts.

Key Maintenance and Repair Chapters

• Engine Overhauls: Comprehensive instructions for decarbonization, valve grinding, and piston/ring replacement. Detailed sections cover the 4G push-rod engines (1948-1959), including specific data for cylinder head torque sequences.
• Transmission and Clutch: Step-by-step dismantling for CP and GB type gearboxes. Learn how to properly adjust primary and rear chains to ensure smooth power delivery.
• Carburetion and Tuning: Tuning and data for Amal (including 10TT9) and S.U. (Type M.C.2) carburetors. Includes high-altitude settings and air filter maintenance.
• Forks and Steering: Service the telescopic front forks with hydraulic control. Covers head races, steering locks, and the 1956-59 assemblies with headlamp cowls.
• Wheels and Brakes: Maintenance for full-width hubs, detachable rear wheels, and brake lining replacement for rigid and pivoted-fork frames.
• Electrical Systems: Detailed test data and overhaul procedures for Lucas and Wipac equipment, Magdynos, dynamos, and alternators.

Vital Specifications and Technical Data

This manual is a goldmine for the "correct" numbers your bike needs to run perfectly:

• Compression Ratios: Detailed for 4G, Mk. I, and Mk. II models.
• Valve Clearances and Timing: Exact settings for inlet and exhaust valves across all engine types.
• Ignition Timing: Points settings and spark plug recommendations to ensure reliable starting.
• Lubrication Tables: Recommended oil grades and flushing intervals (1,000-1,500 miles) to protect your vintage engine.

Why Every Restorer Needs This

Vintage Ariel motorcycles are known for their unique designs—especially the Square Four's specialized crankcase and timing needs. This manual provides the specific knowledge required to prevent damage to light-alloy blocks and ensures you use the correct service tools for every task. Keep your Ariel authentic and high-performing with the same information the factory service agents used.