1980 Triumph Bonneville

1980 Triumph Bonneville Background & History

1980 Triumph Bonneville T140E production kicked off the 1980 model year with Engine #PB25001. But at long last, the last major mechanical improvement in the long history of the Triumph Bonneville was the addition of an electric starter and a new model designation to go with it, T140ES (Electric Starter), starting with Engine #CB29901.

By the time the 1980 Triumph Bonneville came out, what was left of the “Triumph magic” had evaporated. Large numbers of 1979 Triumph motorcycles were still sitting unsold in dealer showrooms and factory warehouses. For the first time since the end of WWII, the home market (Britain) was just about as big as the US market. The Meriden Co-op, already strapped for cash, was up against a wall. But somehow, they soldiered on to give the 1980 Triumph Bonneville a few more years of life. Chalk it up to British determination and toughness.

The 1980 Triumph Bonneville T140E started the model year, joined later by the T140ES which had a long-awaited electric starter.

Incremental Changes to the 1980 Triumph Bonneville

Prior to the T140ES arriving, the only real change to the T140E engine was a new 4-valve oil pump and a modified timing cover to contain it, intended to prevent wet-sumping (a condition common to dry sump machines, in which gravity pushes oil out of the oil tank and through the oil pump, filling up the crankcase while the motorcycle is sitting for long periods). The new pump could be retrofitted to earlier Triumph 650 and 750 unit construction twins provided the new timing cover accompanied it, or the old one was machined. The Lucas Rita electronic ignition first used in 1979 was improved.

1980 Triumph Bonneville gets an Electric Starter

But the real news for the 1980 Triumph Bonneville was the long-awaited, long-overdue addition of an electric starter. By 1980, virtually every new motorcycle on the road had electric starters, all the way down to 250cc lightweights and below. The idea of having to jump on a kickstarter & lunge a big twin into motion seemed primitive, some would say even risky. Have you ever been stuck out in the sun kicking your Brit bike 40 or 50 times in frustration? Yet, when electric starters first became commonplace on 1960s Hondas, they all retained their kickstarters, because people thought an electric starter on a motorcycle was risky. What if the battery goes dead? Good question. By 1980, kickstarters were already disappearing on large bikes with electric starters, such was the change in public perception. Today hardly any motorcycles still have kickstarters. If the bike doesn’t start when they push the little button, most modern riders today wouldn’t have a clue.

This being an early-year 1980 Triumph Bonneville T140E, there is no electric starter.

1980 Triumph Bonneville Electrical Improvements

The new 12-volt Lucas M3 starter motor nestled behind the cylinder block where the magneto used to sit on pre-unit Triumph Bonnevilles and TR6s. Like the old mag, the new starter ran through a gear train (one idler gear bushed on both ends) to the intake cam gear. A new right-side crankcase half and timing cover needed to be cast such that the new timing cover had a removable outer section in the rear which gave access to the 20:1 Borg-Warner sprag clutch. The electrical system was beefed up to handle the new load, with a 14-amp Lucas RM24 3-phase alternator, a Yuasa YB14L battery and a new triple Zener diode pack to cope with each phase separately (leave it to Lucas!). The starter solenoid was hidden under the right side panel & the starter button was on the right handlebar control.

Other Improvements to the 1980 Triumph Bonneville

A larger battery tray was needed, a larger tool box was thrown in, along with mounts for the solenoid & the larger battery required a reconfigured seat pan. A new swinging arm increased tubing diameter from 32mm to 38mm & made both right & left legs the same for production reasons. New upswept exhaust needed new mounts & the footpegs were now raised on all models to clear it.

The front brake master cylinder got an opaque fluid reservoir, the rear master cylinder was relocated, the brake pedal strengthened, & a new rear hub & rotor allowed the speedo drive to be moved from the right to the left side. Smiths gauges were no longer available, so all Triumph Bonnevilles now left with French-made Veglia instruments.

All 1980 Triumph Bonneville seats were now of the stepped design begun with the 1977 Bonneville Silver Jubilee, now all finished in black. All side panels were now black regardless of tank color & all the fenders were now chromed also. The right side panel now had an inspection window for checking rear brake fluid level. The T140D Bonneville Special got shorter fenders than the standard Bonneville T140E.

The 1980 Triumph Bonneville T140E was available in 2 color combos for the UK market and 4 colors in the US. For the UK, there was Steel Gray and Candy Apple Red; Black with White Stripes. The US market got 3 color choices: Black & Candy Apple Red; Olympic Flame and Black; & Steel Gray & Black (shown here in these photos). The 1980 Triumph Bonneville Bonneville Special (T140D) was available in Black with Gold pinstriping in both markets.

1980 Triumph Bonneville Specifications

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1980 Triumph Bonneville Books

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