Suzuki GSX1300R Hayabusa

We put our recent acquisition, Hannibal the 2004 Hayabusa, on the dyno and it scored a respectable torque graph (with a brief dip at 3500rpm), plus a nice and ever-climbing power curve that ended at 164.5 horses at the back tyre in dead stock trim. Which is over the claimed 172 horses at the crank, if you accept one P Tainton's suggestion of adding 15 neddies to the rear-wheel number.

That's healthy, thanks in part to the series upgrade in recent years from a 16 to a 32-bit engine control unit (ECU). It was compensation for the factory-set 296km/h speed limiter that came in about the same time. For around $150, we got over that last 'problem' with a UK-sourced JB Racing timing retard eliminator (an electronic gizmo that plugs into the existing wiring loom) that allegedly removes the 296 restriction and over-rides the 'softer' management of performance in first and second gear. The effect of the latter is minimal - yes, it's more frantic in the upper end of those gears, but not enough to lose sleep over.

All fine and dandy, but there are some more substantial gains to be made.

You can also get 1600cc kits, albeit with the considerable cost of new pistons, conrods and aftermarket long-stroke crankshaft.

We started in a much more gentle way, which was talking to Over Racing importer Don Stafford (of Stafford Motorcycles in Melbourne, pictured kneeling beside the Busa) about a particularly cute four-into-one exhaust system. Cute? Maybe you had to be there, but the titanium headers are an engineer's wet dream. Paper-thin walls and welds that are near-invisible and clearly a work of art. Then there's the big carbon-fibre muffler with stainless steel end caps. All-up it weighs about a third of the stock system - at most.

Since we got onto engine breathing as the starter route for would-be tuners, it made sense to consult someone who could cover the intake side of the equation, plus engine management. No rocket science here: Go to Phil Tainton, who builds and tunes Suzuki's factory superbikes locally, and owns a dyno set-up that can replicate full-noise 'ram-air' induction on a bike breathing in the real world. He also owns a Busa - more on that later.

With the Over Racing system fitted, Hannibal revealed a power graph that was better than the stocker, particularly in the midrange. Top-end was improved, raising the max horses from 164.5 to 170.7. Torque was also up a little. We noticed more enthusiasm to rev in the lower ranges.

There was more to be had, and it took the combination of a BMC race-pattern air filter, a Dynojet Power Commander (an adjustable engine management unit which over-rides the stock ECU), plus lots of dyno time to make the most of it.

We ended up with 177.6hp at 10,000rpm at the back tyre, and 104.8ft-lbs of torque at 7000-8000rpm (up from 99.6). As we mentioned earlier, Tainton says you can safely add about 15 horses to get the at-the-crank horsepower figure - so we're up over 190.

At this stage, the Busa is still very friendly to ride - albeit noticeably more 'boisterous' than previously. It's civil in a Doberman-on-steroids kinda way in normal use, and feral when given its head. A remarkable achievement is the performance of the Over pipe, which remains surprisingly quiet. You wouldn't notice it in traffic, and Tainton was very complimentary about its performance.

The price? Over's full-house titanium and carbon system costs about $3k, while the company offers slip-on mufflers for much less. You could also get a full system for a lower price from other makers. I'm convinced the combination of workmanship, performance and lack of noise (no $2000 fines from the EPA!) of the Over option goes a long way towards justifying the cost.

The Power Commander unit is a well-tried product and worth the money at around $600. BMC's air filter is too expensive at $175, but I cannot argue with the results. By the way, the race-pattern filter is okay for road use, but you're advised to revert to the stocker if any substantial dirt road or dusty riding is on the horizon.

What you really need is a decent tuner (enter Tainton, pictured sitting on the bike) to make all this work. He reckons there's about 2-4 hours of work in this - I'd assume the higher figure. My guess is add up to $1200 (including filter and Power Commander and tuning) to the exhaust system to get the package working better than stock. It's a lot of money, but the results on this bike were stunning. There's more power everywhere. It's predictable and quiet and is unlikely to affect the reliability - a pretty good trick.

Feel free to get in touch via email at guy.allen@tradergroup.com.au.