The 1965 Triumph Bonneville was the third model year since the adoption of unit construction. It represented the culmination of nearly three decades of high performance Triumph twins that stretched all the way back to the 500cc 1938 Triumph 5T Speed Twin, the world’s first ‘modern’ vertical twin, the one that started it all. A year later, Triumph launched hot rod version of its new 500 twin, the 1939 T100 Tiger . In 1950 Triumph punched out their scrappy twin to create the 650cc 6T Thunderbird. In 1954 the hot rod version followed, the T110 Tiger. This was followed in 1956 by the TR6 which introduced the new alloy ‘Delta Head’ that was modified in 1959 to mount a second carburetor, thereby creating the 1959 Triumph Bonneville. The rest is history.
This 1965 Triumph Bonneville is what Triumph looked like at the top of their game.
The 1965 Triumph Bonneville T120 650 was again more or less a carry-over from 1964, which itself was a carry-over from 1963. Changes were minor and evolutionary in nature, aimed at refinement, improving reliability, performance and ease of production. Model designations were also carryovers: T120R was the road machine with down pipes; the T120C was the off-road/street scrambler (like an Enduro); and the TT Special, which wouldn’t actually get its own official model designation until 1966. For now, the TT Special was an option package for the T120C series. The color scheme for 1965 Triumph Bonneville was Pacific Blue over Silver.
LEFT: Non-unit construction (1938-1962) packaged the engine, gearbox and primary chain case as separate components all held together by brackets.
RIGHT: Unit construction (1963-1983) placed these three components in one unitized casing, hence the name.
Engine refinements began with Engine # DU13375 and included a drilled hole in the crankcase behind the cylinder to facilitate finding top dead center, a new oil pressure relief valve, and a change to Champion spark plugs. The exhaust system on the T120R was restyled (more swept back) and brackets added. UK and Export models retained the long mufflers, but US models got a shorter muffler with straight-through baffles. Minor changes were made to the kickstart mechanism, clutch lining material was switched to Armstrong cork, and a longer alternator cable was added to keep it from rubbing on the primary chain.
This 1965 Triumph Bonneville is the T12R, or the 'Road' version.
Frame and running gear also received only minor attention. The rear subframe was modified slightly to make the center stand work better, the horn was hung from a new bracket under the tank, the rear brake actuator rod’s operating arm was moved to the inside of the left engine mounting plate and the rod re-routed accordingly. The battery box received steel liners for its rubber mounts to prevent damage due to overtightening. The QD (Quickly Detachable) rear wheel swapped its taper roller bearings for ball race bearings.
The unit construction engine in the 1965 Triumph Bonneville is a true thing of beauty.
Some US models got all-black seats, while most had the more familiar 2-tone gray-and-black seat, similar to 1964. The new paint colors continued to follow the same pattern as 1964, with the Pacific Blue top covering most of the tank, and the Silver showing only under the tank emblem. Of course the steel front and rear fenders were painted silver with a blue strip running down their center, except for the TT Specials, which sported lightweight polished alloy (aluminum) fenders.
The 1965 Triumph Bonneville T120C was the 'Street Scrambler'-version with it's high side pipes. Many ran no mufflers at all on these, just straight pipes.
The TT Special was officially a Competition version of the T120C Street Scrambler. It wouldn’t get it’s own stand-alone model designation until 1966. But it was much more than simply a stripped-down T120C. The TT Special had bigger carbs (1-3/16″ vs. the standard 1-1/16″), hotter cams (and/or followers), higher compression (11.0:1 vs. 8.5:1) and those gorgeous, big-tube TT pipes sans mufflers. They were fast, especially at higher rpms, but could run hot, due to the high compression. Throughout the 60s, they were almost unbeatable on US scrambles tracks.
This is a 1965 Triumph Bonneville TT Special, optimized for scrambles racing with its signature "TT Pipes". They don't step down in diameter the way the other pipes do, and they duck under the engine, creating cornering clearance. TT Specials came without lights.
Bonneville T120R Bonneville T120C Engine type Displacement Bore & Stroke Compression Carburetors Ignition Engine output Primary drive Primary drive sprockets Clutch Gearbox Ratios, overall: 1st, bottom 2nd 3rd 4th, top Final drive Final drive sprockets Frame type Suspension, front Suspension, rear Brake, front Brake, rear Tire, front Tire, rear Fuel Capacity Wheelbase Seat height Ground clearance Weight, unladen |
Roadster, low pipes Street Scrambler, high pipes Air-cooled OHV vertical twin 649cc / 40.0 ci 71mm X 82mm / 2.79″ X 3.23″ 8.5:1 (T120) / 11.2:1 (TT Special) 2- Amal Monobloc 1-1/16″ / 1-3/16″ (TT) Battery & coil (T120) / Energy Transfer (TT) 46 bhp @ 6500 (T120) / 52 bhp (TT) 3/8″ triplex chain X 84 links 29T X 58T Multi-plate, wet 4-speed constant-mesh, right-foot shift — 11.8:1 8.17 6.76 5.84 5/8″ X .400″ X 3/8″ chain X 106 links 19T X 47T Brazed lug, full-cradle, single downtube Telescopic fork, hydraulic damping Swing arm, 2 Girling dampers 8″ SLS drum, full width 7″ SLS drum 3.25″ X 19″ Dunlop 4.00″ X 18″ Dunlop 2.5 Imp gal (US) / 4 Imp gal (UK & export) 54.5″ / 140.3cm 32.5″ / 77.5cm 5.0″ / 12.7cm 363 lbs / 165 kg |
A meticulously detailed history of the Triumph its antecedents, how it came about, and year-by-year production changes, with detailed tech specs.$98.37 hard bound |
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By Brooklands Books, 172 pages Reprints of motorcycle magazine road tests, racing, new model releases, tech data, specs & more. |
1959 T120 Bonneville
1960 T120 Bonneville
1961 T120 Bonneville
1962 T120 Bonneville
1963 T120 Bonneville
1964 T120 Bonneville
1965 T120 Bonneville
1966 T120 Bonneville
1967 T120 Bonneville
1968 T120 Bonneville
1969 T120 Bonneville
1970 T120 Bonneville
1971 T120 Bonneville
1972 T120 Bonneville
1973 T140 Bonneville
1974 T140 Bonneville
1975 T140 Bonneville
1976 T140 Bonneville
1977 T140 Bonneville
1977 T140J Silver Jubilee
1978 T140 Bonneville
1979 T140 Bonneville
1980 T140 Bonneville
1981 T140 Bonneville
1982 T140 Bonneville
1983 T140 Bonneville
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