1968 Triumph Bonneville T120R 650

sorry to post this but I'm just so happy for my buddy you got to get lucky once in awhile. A shout out to Greg Marsh with his help on the premier carburetors. I'm sure we'll be seeking his advice as well as purchasing some more parts from him.

Fast Eddie said:

IMO the ‘68 US spec is THE best Bonnie. It has all of Douge Hele’s development input and thus is fast, it stops and it handles. It also has an iconic overall design and styling. On later pre OIF bikes the styling got busier and busier. The ‘68 has a design simplicity / purity to it that they don’t.

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His first project was to improve the Triumph Bonneville T120. Drawing from his success with Norton Dominator twins, Hele raised the power output from 47 bhp to 52 bhp on open megaphone exhausts by careful modifications to the design of the camshafts and cam followers. Keen to keep the power gains for road and production racing use, he added a balance pipe between the two exhaust pipes where they exited the cylinder head adjacent to the ports, quieting the engine and allowing use of a less-restrictive silencer. A decrease in exhaust-gas velocity caused by linking each cylinder into effectively two silencers was addressed by reducing the exhaust pipe diameter from 11/2" to 11/4".

That same year, Hopwood’s assistant at Norton, 30-year-old Doug Hele, followed him to BSA. Hele, of course, was later to find fame in his own right as the developer of highly successful racing versions of Triumph’s triples and twins. But back in 1950, he was commissioned by Hopwood to put the BSA 250 single-cylinder racer concept into metal as the prototype for a family of road bikes and also with a possible racing version to be prepared for the Lightweight TT in the Isle of Man, where the Moto Guzzi singles of a comparable overall format were then currently dominant.

Obituary: Doug Hele

Design engineer who fought the last battle of the old British motorcyle industry.

www.theguardian.com

Design engineer who fought the last battle of the old British motorcyle industry

His race mechanics would often bet Doug Hele, who has died aged 82, that he could not measure a piece of metal by eye. The stake was 1s (5p), and he could always get within ten-thousandths of an inch. Doug was one of the few world-class engineers the postwar British motorcycle industry produced, and probably the greatest motorcycle development engineer of all time.

Where can I find a 1960s Bonnie for $1K ? My brother was in South Melbourne a few years ago and a guy had parked one outside a shop. He came out of the shop to find two guys loading it into a utility truck.
1959 Bonnevilles have 8-stud heads. 1963 have 9-stud heads, and 1970s have 10 stud heads. You do not want the light one piece crank, buy the heavy one piece crank and sell the light one. The 5 speed Triumph box is worthwhile. It was first used in the Trident 750.

Sales did not meet expectations; for the 1971 model year a fifth gear was added, creating the BSA A75RV and Triumph T150V. BSA were having financial difficulties, and only some 205 five-speed Rocket 3s were built before production of the BSA variant ceased. Production of the five-speed Triumph T150V (with a front disc brake replacing the original drum) continued until 1974.

For the 1975 model year, the Trident was updated to the T160 which was given electric starting, front and rear disc brakes, and a left-foot gear change. Like the Rocket 3, the T160 also featured a forward-slanted cylinder block, which gave better weight distribution and more space behind the engine for ancillaries.

Triumph Bonneville T140 - Wikipedia

en.wikipedia.org

the first few T140s, designated T140V, featured a larger-capacity engine of 724 cc, a five-speed gearbox and indicators, but still retaining drum brakes and kick-start. Shortly after, the engine was further bored out to 744 cc and front disc brakes were fitted (using single discs until 1982).

acotrel said:

…buy the heavy one piece crank and sell the light one

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Yeah… sell it to me !!