FUELLING

Aftermarket modules or remaps can help get perfect power and throttle response - here’s how and why

THE WAY A motorcycle delivers the fuel into the engine’s combustion chamber is a complex operation that can have a dramatic effect on how a bike feels to ride. Poor fuelling can make a bike’s throttle connection snatchy, harm economy figures and even lead to engine damage, which is why there solutions to alter your bike’s fuelling. So what do they do and what are their benefits?

Why do you need to alter your fuelling?

“The target is to get the air/fuel ratio correct for every throttle position at every rpm in every gear,” explains Frank Wrathall Jnr, MD of Dynojet UK. “Massproduced bikes have to run on varying grades of fuel throughout the world and meet emissions regulations and that means manufacturers have to make fuelling compromises, which you can correct so that the bike is running at its optimum level. Also, if you have modified the bike through a free-flowing exhaust or air filter, you can correct the fuelling to suit. It’s not all about performance; it’s also about making the bike run perfectly, better to ride and more predictable.”

What does a fuelling module actually do?

A fuelling module is a piece of hardware that plugs into the wiring loom between the bike’s ECU and its injectors (it also receives a throttle-position reading), intercepting the standard fuelling signal and altering it before passing it on to the injectors. As it is a piggyback system, it can be removed with no harm to your bike, which is a major benefit, and most manufacturers offer free software which you can upload yourself as they are continually updating maps for bikes tested with various brands of exhausts etc. “The Power Commander knows the exact rpm and throttle position and its fuel table either adds or takes away fuel depending on what is required,” explains Wrathall. “In general, modern motorcycles are very consistent in their build and so you don’t need a specific map or the bike to be dynoed; you can just download and update yourself.”

What does an ECU remap do?

An ECU remap (or reflash) replaces the manufacturers reference data (maps) within the ECU with a custom set of data. “You basically rewrite everything from the fuel maps to the throttle map, ignition map and manifold air-pressure map and, as you are in the bike’s ECU, you can remove any restrictors (top speed, power in certain gears etc) that may be within there, which you generally can’t do with a module,” explains Wrathall. “An ECU remap works well on complicated bikes as you can alter more parameters than with a module.”

What the best solution?

If you have fitted a new exhaust and want a quick, cheap and easy way to alter its fuelling, a module is the best solution. They can be fitted yourself, free maps can be downloaded and they can be removed at any point. But if your bike has a complex issue, like a snatchy throttle, then a remap (and some dyno time) will generally yield a better result.