TO gauge how each end-can affects the bike's performance, we used a dynamometer (dyno), to measure the bike's power. It records this in bhp (brake horsepower) and torque (the force trying to turn the wheel, measured in ft lb.).

Road legal cans were expected to equal, or preferably better, the stock can-tough, as the original FireBlade can is very good. Race cans should increase peak power and give a big increase in throttle response.

We did fast acceleration (FA) and roll on (RO) tests-see Dyno Speak.

Because race cans let the engine take in more air, it's advisable to modify the carbs so they can supply the appropriate amount of fuel. More air plus more fuel lets the bike make more power while maintaining the correct air/fuel ratio. This is called re-jetting. Most re-jetting is done using a Dynojet kit. This has a different air filter, bigger main jets and different profile needles help both fuel flow and throttle response. To get the best from a non-legal race can a bike needs re-jetting so, after all the stock tests were over, we fitted a Dynojet kit to the FireBlade, then re-tested.

The results of all dyno tests were fed into a computer to find the best cans.

Because the non-legal cans were tested with a jetting kit, the results are not directly comparable with the legal cans which can be fitted without modification.

Dynojet prices vary from £40 to £80 for a kit, depending on the bike. Dyno-jetting a Blade costs £60 for an air filter, £88 for the jetting kit and, to do it properly, an hour and a half on the dyno (about £50).