Workshop Walkthrough

Triumph Bonneville T120 unit-construction — four-stage animated walkthrough

A four-stage preview of a Triumph Bonneville T120 family restoration covering the 1963-1972 long-tram 9.5:1 unit twin across T120R / T120T / T120C variants. The teardown stage walks the separated engine / primary-case drain, cam-ring orientation, and the three-stage reverse-torque head lift. The engine stage plays the full procedure on-canvas. The wiring stage previews Lucas electrical work covering the chassis build-month transition from E3L to RM15. The rear + concours stage lands the Uni-Trax swing-arm swap and the 14-step Meriden factory assembly sequence.

Teardown: Drain engine and primary-case lubricant separately on the unit-construction twin, mark the cam-ring orientation to the crankshaft pinion, lift the cylinder head in the three-stage reverse-torque sequence (28 -> 21 -> 14 N-m), and pull the slip joints free before the barrel comes off.