The Engine Team Comes Together
It's difficult to overestimate the amount of time, planning, investment and engineering work it takes to design, test and put into production an all-new engine. There's initial design, computer modeling, prototyping, tooling design, production and testing, power/durability/homologation testing, numerous suppliers to deal with, etc. The costs alone are staggering; I've heard the $10 million number mentioned on occasion, though the actual amount surely varies depending on the type and complexity of the powerplant in question. Still, it's a huge undertaking, and it helps explain Triumph's early focus on the highly efficient modular-engine concept-and why it waited nearly a decade before building nonmodular engines.
The Bonneville engine team had a tough task: marry modern technology (and power and durability, etc.) with classic engine architecture. It wasn't only a difficult assignment, but the success of which was absolutely vital to the project's success. A fragile and/or underwhelming engine could sink the Bonnie just as quickly as an aesthetic treatment that fell short of the mark. And that's a mark etched way, way down the field. This was a Bonneville, remember, a bike considered by many to be the classic Brit-bike. The T120 Bonnie is regarded as a fast, decent-handling and absolutely beautiful machine; it's a reputation that was a constant challenge to the Bonneville team throughout the entire R&D process.
With the team assembled and the engine's most basic parameters-an air/oil-cooled parallel-twin of between 700cc and 800cc of displacement-agreed upon, work began in earnest. Early on, Triumph contracted with engine design and development consultants Ricardo to develop via computer some basic engine specifications (ideal bore and stroke, power and torque curves, etc.). The data would help team members work out the most basic engine-design parameters, allow them to build early prototype parts and begin to look at how to best package the engine itself.
3-D Styling Work Started
Like the engine team, Bonneville stylists and chassis team members had the tricky job of blessing the new Bonnie with thoroughly modern function and a look as close to the original Bonneville's as possible-not easy given the massive gains in chassis development over the last several decades. So they started from ground zero, purchasing a fully restored, 1969-spec T120 Bonnie at great cost, re-importing it to the U.K. from the States, and using it as a baseline for items such as styling, ergonomics, control positioning, etc. "The '69 bike embodies the best possible attributes of the [old] Bonneville," Clifford told me. "We felt it was the right place to start."
With the restored T120 safely ensconced at Hinckley, a whole range of measuring and computer modeling work began. For instance, to get a proportional view of the way a modern engine would look mated to original Bonnie styling and geometry, engineers took a right-side profile photo of the T120 and stripped in an image of an early new-Bonnie engine (from the engine team's early computer-modeling work) in place of the old motor. The result was encouraging. As the basic layout of the new bike took shape on the computer screen (clay modeling wasn't used by Bonneville stylists), a variety of elements began to fall into place, including frame design (with Finite Element analysis ensuring it would be strong enough), desired ergonomics, control positions and chassis geometry. From these chassis parameters, engine team members could begin to nail down the basics and positioning of key engine details, such as output shaft position, engine center of mass and overall size.
British designer John Mockett, who'd worked with Triumph closely over the years, was then tapped to piece together a 3-D styling model to see how the early computer images worked in the flesh. A rough model of the proposed frame was used, along with a wood mockup of the proposed engine, various handmade body parts, and basic suspension and wheel components. While Mockett worked the styling model in late 1997 and into early 1998, the engine team pressed on, working toward the scheduled first run of a prototype Bonnie engine at the end of 1998.