Only the engine carried over from 1970. Not since the 650 twin went unit construction in 1963 ... in the interest of acceleration. 1971 TRIUMPH BONNEVILLE GETS NEW OIL BEARING FRAME Of course, all the ...

The 1950 Triumph Thunderbird was not only the first Thunderbird, it was the first Triumph 650 & it began a long legacy ... 3-piece pressed-together crankshaft & the engine cases were beefed up around ...