The final phase of Triumph twin development began in 1972 with the first appearance of the new enlarged-to-750cc version of the Bonneville, the increase in bore size necessitating a new crankcase to accommodate the larger barrel. Other improvements included a new ten-stud cylinder head, triplex primary chain, stronger transmission and a disc front brake. A five-speed gearbox, introduced on the preceding 650 Bonneville, was standard equipment on the 750. Despite the age of the basic design and strong competition from Japanese and European manufacturers, the Bonnie remained for many years the UK's top-selling 750 and was voted Motor Cycle News 'Machine of the Year' in 1979.

This modified T140 boasts a Norman Hyde alloy swinging arm, fork brace, larger-than-standard front disc brake, 'reverse cone' silencers and a racing-style single seat. We are advised that only 400 miles have been covered since the engine was removed, stripped, de-carbonised, re-bored (+0.060") and fitted with new big-end bearings, etc. In addition, the wheels have rebuilt with new rims and spokes and fitted with new tyres. The machine is described as in generally very good condition and offered with current road fund licence/MoT.