Some more info for 71-72:
The first project from Umberslade Hall that goes into production is a new, tall (31 inches) frame design, with the oil reservoir in its top tube which is fitted to all BSA and Triumph 650 twins (the frame was actually designed for Umberslade by outsider Rob North, on contract). Stephen Mettam, 29, was in charge of the group's five-man styling team. But Umberslade Hall, with 300 employees by 1970, is downsized after the company posts a 2.5 million pound deficit by mid-year. The need to reduce the new design's excess height causes severe production delays for the new bikes. Financial problems also forced Triumph out of racing.
The new Bonnie is called the T120R (R for road). It also incorporates other design changes aside from the oil-bearing frame, including new hubs, twin leading shoe brakes, paper air filters, new headlight, rubber-mounted tachometer and speedometer. But the engine remains the same.
BTW; Those 5 speed gears can be retrofitted to a 4 speed case. I've heard the 5 speed really does not give that much overall advantage, just closer ratio's between gears.
