1972-1973 Yamaha RD250, RD350, DS7, R5C Service Manual

• Built for owners and workshops maintaining the 1972–1973 Yamaha RD250, RD350, DS7, and R5C two-stroke motorcycle series
• Official Yamaha publication P/N SVM-360-0800-20, originally published in September 1972
• Contains 51 exploded-view diagrams, 15 system-layout drawings, and comprehensive electrical charging circuit diagrams
• Delivers 104 pages of technical data detailing the 5-port cylinder and torque induction reed valve engine systems

Engine and Chassis Documentation

This reference guide breaks down the complete two-stroke engine architecture for the early 70s twin-cylinder series. It outlines the Yamaha Autolube automatic lubrication system, focusing specifically on pump stroke checks and oil flow adjustments. Mechanics will find technical breakdowns of the 5-port cylinder induction system. This includes the torque induction reed valve assembly alongside internal components like the crankshaft, transmission shifting forks, and kick-starter mechanisms.

Beyond the powerplant, the documentation covers critical chassis parameters. It details the disc brake hydraulic system construction—specifically master cylinder tolerances, caliper piston specs, and brake hose routing. Steering head ball race maintenance and front fork inner tube dimensions are also mapped out. Proper tire inflation guidelines for varying speeds and riding conditions round out the handling section. Working on vintage motorcycles involves inherent physical risks; always cross-reference these factory baseline specifications with your machine's actual condition and standard workshop safety protocols before riding.

Electrical and Specification Highlights

Electrical system coverage maps out the alternator, regulator, and rectifier circuits. You will find regulator resistance values mapped across various test points in dedicated diagnostic tables. The document provides exact factory torque limits, highlighting bridge bolt values of 60–100 kg-cm and cylinder head tightening at 180 in-lbs (2 kg-m). Tolerance charts establish the minimum pump stroke at 0.20–0.25 mm and piston clearance at 0.040–0.045 mm. All specifications reflect the original engineering standards required for the authentic restoration and maintenance of these classic Yamaha machines.