We are told that electronic fuel injection on the trials motorcycle is the future, but when is this going to happen in trials? This technology is not new in the trials world. Who remembers the Mick Andrews Yamaha YZT 250cc prototype with an early form of
The idea of fuel injection in the trials world came to light in 1996 when forward-thinking Gas Gas played with the idea and employed Spanish engineer Josep Paxau to work on this new project. Working with two young engineers, Josep Parres and Toni Garrido, they fitted an early electronic system to a trials machine. However, when Paxau departed from the Spanish brand in 1997, the idea was put to bed. In a strange turn of events though, the information and experience gained in the world of off-road riding would be introduced to electronic fuel injection, or EFI as it is more commonly known, with Gas Gas on its new 450cc four-stroke enduro machine in 2002.
The first production trials machine to use EFI was Honda’s four-stroke, single cylinder, liquid-cooled one with the introduction of the new Montesa Cota 4RT in 2004. The motor originated from HRC in Japan, based around the single cylinder, four valve OHC CRF 250cc motocross machine. The fuel supply to the engine was by a compact simple integrated injection system (PGM-FI) with a lower volume than a conventional carburettor, aimed at the trials machine. The ECU is an intelligent high-precision control unit which married the throttle body and its control unit together. Its sensors perform instantaneous calculations of a wide range of variables such as the environment, engine temperature and atmospheric pressure to give the optimum performance of the engine. Its success has been well documented, but what about a two-stroke EFI trials machine? The HRC design was, and still is a huge success. Ossa broke new ground with its two-stroke trials model at the end of 2010 with its 280cc reverse-cylinder technology and the introduction of the EFI Kokusan battery-less system.
Trial Magazine tested the new Ossa and it was very good, with the engine offering a very linear performance with no sudden power surges reported; the chance to stall the motor even on very low throttle openings had vanished. The problem was that it was complicated to adjust, meaning a trip to the dealer or importer to make any changes.
Spanish brand Vertigo is the latest manufacturer in trials to introduce EFI on its two-stroke models. The very compact engines benefit from a bespoke electronic system representing the latest advances, with the electronic control unit managing and controlling the performance of the engine in all situations. With a choice of four different maps in each of the six gears the rider has access to 24 maps, allowing an unequalled level of user refinement in the world of trials. Once again though, as with the Ossa, to make any adjustments is not as easy as on the good-old mechanical carburettor and it also requires a certain amount of knowledge to make changes.
It’s quite understandable why the manufacturers need to look at the electronic fuel injection systems with the introduction of the Euro 4 homologation regulations concerning emissions, but will the changes to meet these new rules come from the fuel manufacturer itself?
Just over twenty years ago, I was working in Research and Development in the automotive industry and one of the world-leading car manufacturers gave us a talk on the future of diesel engines in motor vehicles. They said that by the year 2020 diesel fuel would be a thing of the past and that a two-stroke car or hybrid electric/fuel motor vehicle is where we would be at with emission controls. Only time will tell who will be correct, but one thing is for sure is that change is happening whether we like it or not. Or, will we all go electric?
Montesa/Honda was the first manufacturer to successfully use fuel injection on its production four-stroke Cota 4RT trials machines.
Jeroni Fajardo looks for the correct map as he programmes the electronic fuel injection with his mechanic for the Japanese world round.