1969 Triumph Bonneville

1969 Triumph Bonneville Background & History

The 1969 Triumph Bonneville had its work cut out for it. It seemed like the Bonneville was getting faster every year, and good thing too, with new arrivals from Japan like the 1969 Honda 750/Four & the Kawasaki 500 triple. The merry men at Meriden found a few more horses hiding in the venerable vertical twin yet again. These were the Golden Years for the Triumph Bonneville and Triumph motorcycles in general, the last time they would be considered a world-class performance motorcycle. When compared to the increasingly technologically-superior, better built, and cheaper bikes from Honda, Yamaha, Kawasaki and Suzuki, the Triumph Bonneville looked outdated and outclassed. The end was near, but no one knew it yet. The model designations were as before, T120R the road version with down pipes; T120C, the off-road/street scrambler with high pipes. The 1969 model year began with Engine #DU85904.

1969 Triumph Bonneville Engine Mods

Starting with Engine #DU86965, the 1969 Triumph Bonneville engine numbers were stamped over a series of embossed Triumph logos on the number plate at the base of the cylinder block, on the drive side (left side). Inside the engine, the cams were now nitrate-hardened (marked with an “N”) that solved earlier wear problems. Starting with Engine #DU85904 new revised Hepolite pistons with domed crowns & strengthened gudgeon pins (we Yanks call them wrist pins) and from Engine #GC23016, new connecting rods with self-locking cap nuts were used. In yet another attempt to solve the vibration problem, weight removed from the flywheel in 1968 was put back on, while retaining the 85% balance factor, starting with Engine #NC02256.

Numerous smaller changes were made to the pushrod tubes, the oil pump and the continuing conversion over to Unified threads (American) from British Standard (Whitworth) which started in 1967. The twin 30mm Amal Concentric carbs on the 1969 Triumph Bonneville, now rubber-mounted, lost their separate pilot jets, relying instead on a fixed internal drilling. Main jets went from 210 to 190 and needle jets from 0.107 to 0.106. The gearbox was almost completely reworked and beefed-up, in stages: new shift mechanism, extra hardening of the gears, ‘shaving the gears’, larger main- and layshafts. Starting with Engine #DU88383, the clutch baskets were statically balanced.

All of this added up to an additional 3 horsepower on top of the 1968’s 46. Hence, the 1969 Triumph Bonneville made 49 horsepower at 6200 rpm, making it the most powerful Bonneville ever, at least up to this point. The 8-valve 1983 Triumph TSS topped it with 58 hp. But that’s another story.

By this time, the 1969 Triumph Bonneville was starting to lose its edge.  It was starting to look old-fashioned when compared to the 'modern' Japanese bikes.

1969 Triumph Bonneville Frame & Running Gear

The frame remained virtually unchanged for 1969, but the fork yokes (triple clamps) were made 1/4′ wider to allow for wider front tires. The new-for-1968 8-inch TLS front brake needed some work, including the rerouting of the cable.

The seat now had a quilted top of a breathable fabric and thicker padding. The “eyebrow” tank emblem was replaced with a simpler one. Colors for 1970 were Olympic Flame (a deep reddish-orange) & Silver, with the usual pattern on UK/Exports. A new paint scheme on US bikes, where the Silver on the tank was shaped into a flash, below the tank emblem and in front of the knee pads. The steel fenders were now painted Silver with an Olympic Flame stripe down the center. Some US machines had this reversed. Gold pin striping separated the two colors. The gold “Bonneville” transfers on the black oil tank and left side cover were now in block letters, instead of the traditional script.

1969 Triumph Bonneville Specifications

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Triumph Bonneville Books

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More Triumph Bonneville Pages

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

1983 TSS Bonneville

1983 TSX Bonneville

1983 TSS Bonneville

1983 TSX Bonneville

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