The VFR's illustrious V4 engine has a proud history of powerful, high-revving performance with a soul that other's only strive for.

For 2002 and a new generation, with the VFR reborn as a more dynamic and formidable sports tourer, this unique, high-performance V4 engine was completely revised to achieve a stronger surge of low-to-midrange power output coupled with the added benefits of lower noise and lower emissions, all while maintaining the VFR's traditional Honda V4 power characteristics.

Until now, the VFR's most impressive power output has been of the high-revving 4-valve variety. But with the introduction of its revolutionary new V4 VTEC system, the new VFR's engine delivers stronger, more responsive torque and power output at low-to-midrange engine speeds, and then switches valve operation at higher engine speeds to deliver a bigger top end surge. Amazingly enough, this major boost in total performance was achieved without the slightest change to its bore, stroke, throttle bore, crankshaft or other internal engine specifications.

The most revolutionary development in the VFR's new engine is the introduction of a revolutionary new two-stage 'V4 VTEC' valve control system which combines the best power characteristics of both 2-valve and 4-valve combustion chamber designs.

Basically, this highly effective new system keeps the engine running on two valves per cylinder at low to midrange engine speeds in order to maximize the engine's thrust of smooth, strong low-end torque, then switches to full 4-valve operation at higher engine speeds to take advantage of this configuration's high-rev power characteristics, thus achieving the best of both worlds of engine design.

The new VFR's unique V4 VTEC system features a set of compact, hydraulically actuated lifter sleeves installed inside the inverted buckets of the valvetrain's direct-actuation valve lifters, over one intake valve and one exhaust valve in each cylinder. During low-to-midrange operation, the lifter sleeves slide benignly up and down over the tops of the valve stems, allowing only two valves in each cylinder to open to maintain the enhanced torque and powerful thrust of responsive low-end power and acceleration associated with the best 2-valve engines.

At around 7,000 rpm the entire personality of the engine suddenly changes, as a burst of oil pressure to the lifter sleeves forces their spring-loaded engagement pins to slide across the centre hole and initiate actuation of the remaining two valves of each cylinder. The engine suddenly comes on cam, full 4-valve operation kicks in, and the tachometer needle takes a dramatic leap toward redline in the characteristic rush of high-rev power commonly associated with the most high-performance 4-valve 4-stroke engines.

In achieving the best of both worlds of 4-stroke engine design, the V4 VTEC system also gives a further boost to the VFR's midrange performance to provide a more linear surge of acceleration that seems to instantly jump in response to throttle input from virtually anywhere in the rev range, rather than building up slowly to a conventional 4-valve engine's peak power-producing revs.

One unmistakable result of this new 2-stage power output is the exceptional roll-on performance the new VFR delivers at the twist of its throttle-even when fully loaded for touring with passenger and gear. Overtaking becomes such a revelation that one would be forgiven for thinking there's a few more cc's hidden away in that compact V4.

Another benefit of the VFR's new V4 VTEC system is its quieter operation at lower speeds. Since only one intake and exhaust valve opens at each stroke, air moves more gradually into and out of the combustion chambers at low-to-midrange engine speeds, releasing pent-up exhaust gases more quietly and reducing blow-back when the intake valves open. The new system thus provides smoother, quieter, more torquey, and more comfortable response to throttle inputs for in-town riding at lower, more 'civilised' engine speeds.

However, turn up the revs past 7,000rpms and the VFR's engine comes really alive with 4-valves in full operation.

The new VFR's V4 VTEC-controlled intake and exhaust aren't the only areas where efforts were made to reduce noise. The engine's famed high-tech gear-driven valvetrain has been replaced with a new 'Silent' camchain drive that not only greatly reduces mechanical noise, but also reduces the engine's overall weight by nearly 3kg, for quieter, more civilised operation around town as well as for more relaxing long-distance rides. The system's two sets of dual tensioners are equipped with spring-loaded screw-action lifters that maintain steady pressure on the cam chains throughout the engine's wide rev range.

Another major benefit of this switch to chain-driven cams is the narrower valve angles made possible by the camshafts' smaller driven gears. This new 1.5-degree narrower included valve angle makes a significant contribution to the engine's more compact combustion chambers, helping to realise a higher filling rate, greater combustion efficiency and stronger overall power output.  Personally I would rather have the whine of a gear drive and the aural pleasure it provides.

The VFR's superb, high-accuracy PGM-FI fuel injection system has also been upgraded with a set of new 12-hole injectors replacing the 1-hole injectors currently used to realise finer fuel atomisation, resulting in more efficient fuel combustion for stronger, cleaner and more stable performance.

Combustion efficiency is also aided by new, hot-firing iridium spark plugs, which are ignited by compact, new, high-energy 'coil-on-plug' spark plug caps (like those used on the CBR600F). These combine to produce a stronger, higher-voltage spark for quick, high-efficiency combustion and sharper, more responsive performance.

Another benefit of these improvements to the VFR's combustion efficiency, which adds up to more than a 20% increase in fuel efficiency over its earlier carburetted version. This dramatic improvement in fuel efficiency combines with the VFR's new 1-litre larger fuel tank to realise a markedly longer touring range on a single tankful of fuel, keeping fuel stops to a more comfortable minimum while greatly reducing fuel costs over the long term.

While most conventional cylinder sleeves are cast into the cylinder block with their top rims, or flanges, sunk in flush with the top deck of the cylinder, the VFR's low-friction aluminium/ceramic composite cylinder sleeves have no top flange, and their upper edges are instead set in 3mm below the surface of the top deck. This new 'flangeless' design enhances cooling efficiency by permitting the cylinder's uppermost hot spot above the top piston ring to more quickly and effectively bleed-off combustion heat directly to the coolant jacket, with less interference from the cylinder sleeves in this critical area.

The combustion chambers' new ultra-compact, high-compression design also features a 30% thinner head gasket that helps minimise the 'quenching area' that normally exists in the corner gap between the head and cylinder block, improving the igniting flame's reach into the far recesses of the combustion chamber and realising a significant increase in cleaner-burning combustion efficiency.