1981 Triumph Bonneville

1981 Triumph Bonneville Background & History

The 1981 Triumph Bonneville attempted to address dwindling sales with what had become “Limited Edition”-madness. Not that it was a bad thing, they turned out some pretty nice bikes. But, the problems Triumph was facing couldn’t be solved by cobbling together yet another tarted up version of the same old tired 1937 design. But, that didn’t stop them. More power to ’em!  Frankly, few choices remained.  Triumph was producing fewer and fewer bikes each year, the all-important US market was starting to lose interest in what had become a retro niche bike, and they were running right at the edge of financial collapse at all times.  Triumph simply didn’t have the money to fix the problem, which would have taken a complete redesign of their products.  And now they were relegated to producing Bonnevilles in small batches because they couldn’t afford to buy supplier components (like lights, controls, brakes, cables, chains, and so forth) in bulk.  Building bikes in small batches with a mixed bag of parts was not good business, but it made it easier to spin off special variants.

The 1981 Triumph Bonneville was available in more colors than ever before.

3 New Versions of the 1981 Triumph Bonneville

Meriden came out with no fewer than 3 new versions of the 1981 Triumph Bonneville. The first two were variants of the Bonneville Executive, meant to be the touring version, in both kickstart (E) and electric start variants (ES). These came with fairings, top box (touring pack) and panniers (hard saddle bags). The third bike was intended for Police duty and was being evaluated for that purpose. This final 1981 Triumph Bonneville variant was called the T140AV, the “AV” ambitiously designating “Anit-Vibration”, which used rubberized engine mounts to quell the vibes. At that time, BMWs boxer-twins were getting the lions share of Police business in Europe and the UK, partly because they were very smooth, but also absolutely reliable. Neither of which could be said for the Triumph Bonneville, unfortunately.

1981 Triumph Bonneville Engine Mods

The 1981 Triumph Bonneville model year began with Engine #KD28001. Engine mods were few. The TDC locating hole was itself relocated to its former position in front of the engine, because the starter was now in the way and the crankshaft was notched accordingly. There was a new heavy duty 4-lipped roller main bearing on the timing side. The oil feed to the exhaust tappets was blocked off. The old-style screw-in exhaust spigots and finned clamps made their return. Oil seals were added to the exhaust valve guides.

This 1981 Triumph Bonneville is finished in the Astral Blue and Silver paint scheme.

New Carbs for the 1981 Triumph Bonneville

Ever tightening emissions standards forced a move from the Amal Concentric MkII carburetors to the 32mm German-made Bing Type 32 CV (Constant Velocity) carbs for the US market. Early T140Es and T140ESs and all home-market 1981 Triumph Bonneville Executive models were delivered with the Amal MkIIs. The clutch was massaged with thinner plates with cork faces, down to 6 plates from 7 and lighter springs were installed. Starting mid-year, the higher-output alternator of the ES version was now installed on all units, with or without electric start, presumably to simplify production.

This one's finished in Flame Red and White.

More Changes for the 1981 Triumph Bonneville

Midyear, Morris alloy wheels replaced the Lesters and were optional on all models.  Dual front disk brakes also became optional midyear, being introduced first on the Executive.  Late in the year, all brake discs lost their chrome finish, and a more effective Dunlop friction material was specified.  A new ‘king & queen’ seat was used on the Executive.  Mudguards (fenders) went from chrome to polished stainless on all Bonneville models except the Executive, which had painted fenders to match the tank.

Partway through the 1981 production run, Triumph started running out of the traditional British-made tanks that everyone was used to seeing on Triumphs.  What few remained were used on E and ES models and early UK-market Executives.  From then on the tanks were made in Italy.  While they retained the same center-bolt mounting, they were shaped differently and had a flip-up filler cap, with a lock on US bikes. British and ‘export’ bikes got plain Triumph tank badges, while US-bound bikes retained the chromed ‘eyebrow’ tank badge.

The Silver and Black paint combo was particularly handsome.

6 Colors of 1981 Triumph Bonneville

Both US and UK 1981 Triumph Bonnevilles were now available in six color combinations, as Triumph sought to attract customers of every taste.  US bikes now came with two smoked paint schemes, Smoked Astral Blue with a Silver scallop above the tank badge, and Smoked Olympic Flame with an Ivory scallop, both with gold pinstriping.  Side panels now matched the tanks with the smoked effect fading from front-to-back.  The rest of the pallet were all pinstriped in gold and included Steel Gray with Black; Black with Candy Apple Red; Silver Blue with Black; and all Black.  The Brits got a couple of their own color schemes: Steel Gray with Candy Apple Red, and all UK bikes got double gold pinstripes whereas US 1981 Triumph Bonnevilles got single stripes.

Seeking New Suppliers

As a sign of the times, Triumph Motorcycles ceased to be the high-volume component purchaser it had once been, so many of its suppliers moved on. Girling rear shocks & Lucas chromed turn signals ran out mid-year and had to be sourced elsewhere, including France and Italy. Time was running out for the Triumph Bonneville. Pity, that.

1981 Triumph Bonneville Executive

The 1981 Triumph Bonneville Executive was Triumph's premium bike, it's touring edition.  The all had the UK-market 'bulldog' tank and rubber front fork gators.  They were also the only 1981 Bonnevilles without polished stainless fenders, with the exception of the TSX.  The Executive came from the factory with a fairing with windshield, a set of hard panniers (saddlebags), and a hard top box.  All were well made and painted to match the bikes smoked paint job.

1981 Triumph Bonneville T140AV 'Anti-Vibration'

The scrappy Meriden Co-Op was trying many things to attract new markets and more sales for their aging Triumph Bonneville.  One promising market was law enforcement, and Britain and her former Empire had lots of it.  Sales of the ugly 'LE' to law enforcement literally saved the Ariel Motorcycle Company in the late 1950s.  Maybe Triumph could have the same luck.  The problem was that British law enforcement agencies had largely adopted BMW's boxer twins, because of their reliability and most of all their smoothness.  The Triumph Bonneville didn't have either of these two attributes and reliability had proved to be a troublesome bogie.  So, they thought if perhaps they could smooth out the Bonneville's ride perhaps they could win some of these much-needed contracts.  So, Triumph reengineered the Bonneville's frame to closely copy the Norton Commando's Isolastic Suspension whereby the engine became the swing arm pivot and the whole thing was rubber mounted in the frame.  What few T140AV's (AV stood for Anti-Vibration) were built were one-off prototypes, many using Norton parts.  At the end just seven TR7AVs were built but the police contracts never came.  The intention was to move the technology over to the Bonneville Executive first and then spread it across the entire Bonneville line.  Alas events overtook them and they simply didn't have the money to make the changes.

1981 Triumph Bonneville Specifications

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1981 Triumph Bonneville Books

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1970 T120 Bonneville

1971 T120 Bonneville

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1983 TSX Bonneville

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