1970-1973 Triumph 650cc Twin T120R/TR6R/TR6C Models Workshop Manual (OEM)

• Official Triumph Engineering Co. Ltd. publication (1972 first edition) covering the 1970–1973 T120R Bonneville, TR6R Tiger, and TR6C Trophy.
• Documents both 4-speed and 5-speed transmission configurations, highlighting the transition to early 70s US-market specifications.
• Contains 213 pages of exact technical specifications, maintenance intervals, and exploded-view mechanical diagrams.

Technical Documentation and Content

The 1970–1973 Triumph 650cc twin workshop manual provides essential bench reference material for servicing the T120R and TR6 series. This factory publication fully details the unit-construction engine architecture. It outlines diagnostic and mechanical procedures for the crankcase, the forged two-throw crankshaft, and valve timing. The manual also breaks down the entire lubrication system. Additional chapters cover tuning the concentric Amal carburetors, setting ignition timing for the contact breaker mechanism, and adjusting the transmission components, including the multi-plate clutch and shock-absorber unit.

For the chassis, mechanics will find detailed frame and attachment data alongside scheduled maintenance for telescopic forks and wheel bearings. Exploded diagrams offer clear visual context for the engine, gearbox, clutch assembly, and exhaust routing. Understanding these original factory layouts is vital for accurate diagnostics on classic air-cooled British motorcycles. Always cross-reference these original procedures and ensure you have the proper technical background before beginning hands-on work, as vintage motorcycles require precise mechanical handling to operate safely.

Specification Highlights

Factory technical sections deliver the required torque values, clearances, and fluid capacities specifically for the 650cc twin platform. The engine assembly data specifies a flywheel bolt torque of 33 ft·lbs (4.6 kg·m). Outer cylinder head bolts require 18 ft·lbs (2.49 kg·m). The recommended oil reservoir capacity is 3 imperial gallons.

Clearances are equally precise. The intake valve clearance is listed at 0.002 inches. Piston ring gap is set between 0.010 and 0.014 inches. Final-stage ignition timing maps at 38° B.T.D.C. All specifications reflect the original factory engineering data for these specific models, ensuring historical accuracy for rebuilds and restorations.