1978-1987 Honda 400, 450 Twins Service Manual (P/N M334, Clymer)

• Detailed technical data and maintenance procedures for the complete series of 400cc and 450cc parallel-twin motorcycles.
• Official Clymer publication (M334, 12th printing) detailing engine, chassis, and electrical system specifications.
• Features 14 distinct chapters with exploded-view diagrams, wiring schematics, and specialized tables for routine service or complete repair.
• Contains 8 maintenance and tune-up tables specifically covering the CB400, CM400, CM450, and Rebel 450 models.
• Documents requirements for both 5-speed manual and automatic transmissions (Hondamatic) across the production lifespan.
• Highlights specific differences between the early 400cc machines and the later Rebel 450 updates.

Technical Breakdown and Workshop Application

This manual details the critical systems: engine, clutch, fuel, exhaust, suspension, and electrical. Designed for daily workshop use, it organizes content by functional assemblies to speed up diagnostic work and part identification. Before starting any maintenance, technicians should review the included fundamental guide covering essential tools and vital safety practices to prevent injury or equipment damage. The general information section establishes standardized torque values and conversion charts necessary for assembling internal engine and chassis components securely.

Key Specifications and Reference Data

Accessing precise measurements is crucial for an accurate repair. The text provides specific valve clearance tolerances, distinguishing idle speed settings for automatic versus manual models. You will find torque specifications for critical hardware, such as cylinder head bolts and balancer chain adjusters, listed in both Newton-meters and foot-pounds. Additional data covers tire pressure guidelines, front fork oil capacities, and drive chain replacement part numbers. For instance, the engine specification table lists the intake valve clearance at 0.08–0.12 mm. Rebuilding the automatic transmission requires a documented oil capacity of 3.3 liters. Furthermore, advance ignition timing is specified at 4,500–5,350 rpm. This 411-page resource equips mechanics with the exact factory numbers needed to handle routine servicing and complex overhauls.