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2003 Triumph Bonneville T100

Triumph really has done a nice job with the new Bonneville. Introduced in 2001, it is now their largest selling model. No surprise really, it has all the charisma of the 60's era bikes with none of the vices. They don't leak oil, don't break down, don't vibrate (due to the balance shaft), and they shift better than any of my recent bikes.

Knowing they needed to bring back the Bonneville at some point, Triumph waited and did it right. As with their other engine families, the Bonneville engine was designed by Cosworth, famous as a premier designer of all manner of state-of-the-art race car engines and chassis.

Take a look at these pics and you can see the superlataive job they've done combining modern technology with classic Triumph looks.

As mentioned, all new bikes are made to conform to EPA noise and emission standards. This causes some compromises in several areas, therefore some adjustments are required to get the bike to both run and sound right. Below I've detailed the mods I've made. I'm very happy with the results.

Triumph accessories (all of which really should come with the bike):

  • Centerstand
  • Rear rail and grab bar
  • Chrome valve covers
  • Triumph "Off Road" mufflers (aka TOR)
  • Countershaft sprocket changed from 17 to 18 tooth


  • Air injection system removed
  • Restrictor plate removed from airbox
  • Air filter element replaced with Uni foam type
  • Airbox intake snorkel removed
  • Pilot jet changed from #40 to #42
  • Main jet changed from #110 to 135 main
  • 2 shims added under carb needle boss (raises needle)
  • Idle mixture block cap removed, screws set to 2.5 turns out
  • Stock mufflers replaced first with Triumph "off-roads" (TOR), then with Toga "peashooters" from Norman Hyde in England. Toga is the manufacturer of the original mufflers for 60's era Triumphs so these provide a more "authentic" sound. The TORs definitely better than the stock mufflers, but still don't sound quite like the Bonneville's of the 60's, the Toga's do. Frankly, the TORs are what the bike should come with as stock.
  • Mufflers replaced again with Staintune reverse cone units, best so far, fabulous quality, excellent sound. I sold the Togas, threw away the stock mufflers, and am keeping the TORs as a "stock" muffler in case I want to go back to that look and sound.
  • Norman Hyde "M" bars installed (after trying two other types for the "right" fit).
  • Ikon (formerly Koni) rear shocks installed
  • Ikon fork springs installed
  • Speedo error - Soon after getting my bike I sensed the speedo might be off a bit and so checked it with a GPS. Sure enough, it was reading 10% high across the all speed ranges. I contacted Triumph who said "that error is within our spec and we will not correct it". Not satisfied, I removed the speedometer and had it recalibrated by a local speedometer shop. Be advised though that once you remove the speedo it will appear permanently sealed by the chrome faceplate bezel. Based on a tip from an online forum I was advised that it is possible to use a screwdriver to pry the bezel back. You will scar the plastic housing and the bezel when doing it, but when reassembling by reforming the bezel flange flat the damage will be completely hidden by the rubber ring the speedo sets in. I took the speedo mechanism to a local speedometer shop and he was able to quickly tweak the spring to adjust it right on at 60 mph — much better!
  • I've found that optimum tire pressures are 34 front / 38 rear

In total these changes really transform the bike so it runs, sounds, and handles like it should. The suspension changes make the ride noticably more supple and "planted" feeling with proper damping. The carburetor changes enable it to run properly with no stumbling or lean surging commonly found on newer "EPA lean" bikes. The handlebars lean the rider just a bit more forward to better deal with the wind when on the freeway, and the exhaust provides a proper Triumph sound while not being too loud. Many of the above parts were sourced from including the air injection elimination kit, Uni air filter, and carburetor jets.

For those interested in finding out more about these mods, or just exchanging information with other Triumph owners, there are two online resourses I'd recommend...

The New Triumph Bonneville Forum (DelphiForums)

My Bonneville...


A condensed history of Triumph...

Siegfried Bettmann founded the Triumph Cycle Company in 1887 and promptly acquired premises in Coventry in which he began manufacturing bicycles. As technology advanced the company moved into the production of powered cycles in 1902. By 1905 the factory output had reached 500 motorcycles per year, with the machines being designed, manufactured and built at the Coventry site.

For the next 18 years Triumph enjoyed steady growth and in 1923 the company added automobile production to their portfolio. By 1925 the motorcycle plant in Coventry occupied 500,000-sq. ft. and employed 3000 people; with production at around 25-30,000 units per year.

The motorcycle industry remained fairly stable throughout the early 1930s, and in 1935 the decision was taken to separate the car and motorcycle divisions (the bicycle business had been sold off in 1932). In due course the motorcycle arm was sold and renamed Triumph Engineering Co.

During the Second World War, the Government requisitioned virtually all of the machines manufactured and, despite the Coventry factory being destroyed in the 1942 Blitz of Coventry, production continued throughout the war years, firstly at a temporary site in Warwick and then at a new factory in Meriden.

Civilian production began again in 1946 and with supply lines open again Triumph set about re-establishing a dealer network in America. In 1951 the BSA group bought Triumph, although the Triumph marque was retained and the company remained a separate concern within the group.

Production and sales had grown steadily since the war and by 1965 the Meriden plant was producing around 800 units per week, with 80% of these destined for the USA. Production peaked in 1969 at around 46,800 units per year. In 1968 the first triple - the Triumph Trident - was produced (prior to this the company had concentrated on the manufacture of singles and twins).

By the early 70's the slow supply of components, coupled with tooling problems led to production delays and in 1972, in a Government sponsored move, the BSA Group merged with Norton Villiers and Norton-Villiers-Triumph (NVT) was formed. In 1973 NVT announced that the Meriden plant was to close, which provoked a workers' sit in. As a result production ground to a halt and in the following year, 1974, virtually no motorcycles were built. In 1975, after much negotiation, the Meriden Workers Co-operative was formed and, with capital provided by way of a grant from the British government, production of 750cc Bonnevilles and Tigers resumed at the plant. The co-operative subsequently bought the rights to the Triumph marque from NVT and production gradually crept up to 350 units per week. Despite further support from the government the co-operative went into liquidation in 1983.

The intellectual property rights to the Triumph marque were subsequently bought by John Bloor. Thus began the current era of Hinckley built Triumphs.

The new company needed a strong and stable platform from which a range of competitive motorcycles could be developed, thus the concept of the modular range was born. This concept enabled the range to share common components, thus allowing a number of different types of machine to be constructed from the same base which, crucially, could all be built on one assembly line at the same time.

Design of the new range commenced in 1984 and by 1988 the company was ready to begin building a new factory (the old plant at Meriden had been demolished in the early 80s). A 10-acre site was purchased in Hinckley, Leicestershire, England and construction commenced. As soon as the first phase of the site was complete, pre-production began and the first models were launched at the Cologne show of 1990. Production of the first new model - the 4-cylinder 1200cc Trophy - began in early 1991, with the factory initially building 8 - 10 new machines per day.
As production capacity steadily grew, Triumph set about re-establishing a network of export distributors. Two subsidiary companies had been established to prior to production commencing; Triumph Deutschland GmbH and Triumph France SA and over the next couple of years the network expanded to encompass most of the World's major motorcycle markets, culminating in 1994 with the creation of Triumph Motorcycles America Ltd.

By this time 20,000 new Triumphs had been built and in January 1995 the Triple Connection clothing range and the accessories range of products were launched to provide the Triumph customer with an all-round package of Triumph apparel and equipment. Production now stood at around 12,000 units a year and as both retail sales and production capacity grew the company was able to develop more single-minded machines that did not rely on the modular concept. The first of these, the Daytona T595 and the T509 Speed Triple, were launched at the 1996 Cologne Show. The range diversified further with the introduction of the Sprint RS and ST, the Tiger and more recently with the launch of the TT600 and Hinckley's first twin; the Bonneville.

Triumph has now produced over 140,000 motorcycles and output at the factory is steady at around 140 units per day, which is the maximum that can be achieved at the existing site. In anticipation of this planning permission for a new factory was sought a number of years ago. The construction of Phase one of the new factory was completed in the autumn of 1999 and the transfer of certain manufacturing processes is well underway. For example all steel spine frames are now being manufactured at the new site and the twin-cylinder engine's crankcase and cylinder head lines are located there. When fully operational the new factory will raise Triumph's production capacity to around 50,000 motorcycles per annum.


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