Honda CB250/CL250/CB350/CL350 1960s-1970s Shop Manual (P/N 07000-28601)

• Covers 1968 and later Honda CB250, CL250, CB350, and CL350 vertical twin-cylinder motorcycles
• Original OEM publication directly from the Honda Motor Co., Ltd. Service Division, P/N 07000-28601
• Includes 219 pages of factory technical specifications, exploded-view diagrams, and descriptive repair information
• Details critical components like the contact breaker, spark advancer, A.C. generator, starting motor, and starting clutch
• Highlights the cam chain tensioner, gear shift assembly, kick starter, steering stem, and wire harness

Engine and Transmission Architecture

The 1968 and later Honda twin-cylinder platform requires precise data for accurate workshop processes. This PDF manual breaks down the complete mechanical layout of the O.H.C. air-cooled twin. You get detailed structural overviews covering engine construction, dismounting, and remounting. Specialized chapters examine the cam case, cylinder head, and valve mechanism. Every technical section carefully explains the layout and operation of the constant-velocity Keihin carburetor, clutch assembly, and the five-speed transmission system. Instead of relying on expensive dealership labor, DIYers and mechanics can follow the step-by-step instructions for complete engine tune-ups, valve seat refacing, and splitting the upper and lower crankcases.

Expect comprehensive data previews to support your workflow. The reference tables provide essential figures, including engine performance curves, driving performance curves, sectional views, and dimensional drawings. Need special tools? It lists the exact factory units required for servicing valves, pistons, and crankcase components. Cylinder head bolt torque values are strictly documented at 60–70 kg-cm, while center bearing cap bolts call for 160-210 kg-cm. When servicing these vintage twins, professionals must pay close attention to the centrifugal oil filter hidden inside the right cover; it requires regular manual cleaning, as neglecting it frequently leads to upper-end oil starvation and severe camshaft scoring. Additionally, improperly setting the automatic hydraulic cam chain tensioner can result in erratic valve timing and valvetrain damage. Before starting any project, always verify that your workspace meets standard safety protocols, as handling heavy engine components and pressurized fluids requires proper protective gear and extreme caution.

Frame, Chassis, and Electrical Specifications

A proper motorcycle restoration goes far beyond the powertrain. Frame sections detail the handle, front fork hydraulic dampers, fuel tank maintenance, and braking system service limits, providing the exact procedures needed for cost-saving front fork rebuilds. To help you trace electrical issues during a repair, the publication includes complete wiring diagrams for various market types. A dedicated section outlines the steps to identify common running irregularities using specific diagnostic methods and troubleshooting charts. You will find exact 12V-12AH battery charging system characteristics, stator testing procedures, and selenium rectifier values. Engine oil capacity for the wet sump lubrication system is correctly noted at 2 liters, alongside precise tolerance charts for gear shift forks and wheel hub clearance. Having direct access to these strict factory specifications allows you to accurately fix worn components, eliminating guesswork and drastically reducing customer comebacks in daily workshop operations.