It's long been known that V-twins (and, to a lesser extent, V-fours) don't spin their rear wheels as easily as inline four-cylinder bikes because the tyre has more time to recover between the (admittedly bigger) power impulses - the so-called "Big Bang" effect.
But straight fours make more power and in some applications - such as GP racing - that's more important.
However, about 20 years ago somebody figured out that if you rearranged the crankpins on a 500cc GP two-stroke so that two cylinders fired in rapid succession with a pause before firing the other two close together, you'd all the benefits of a V-motor with most of the power of a four.
Fast-forward two decades and first Kawasaki and then Yamaha discover that the same applies to four-stroke MotoGP engines - and now Yamaha has brought the 'Big Bang' engine to the street with the 2009 R1.
So how different is it to a "conventional" four-cylinder engine? In a word, totally.
It sounds different: the '09 R1 sounds like a Honda VFR800 but with even more of a flat, angry edge - and it's noticeably louder than its predecessor even with factory pipes.
It vibrates: the new R1's irregularly spaced power impulses create a lot more shakes (and a bit more mechanical clatter) than the competition. If you grew up on turbine-smooth midweight fours you may not "get it" but if your formative motorcycling experiences were of singles or twins you'll understand what this engine is saying.
There's a hint of power-thudding just off idle and a distinct primary thumping in the midrange that says "I'm working hard and loving it", with a hard-edged thrumming at the top that you're always aware of although your primary focus is on the fact that next week is approaching at an alarming rate.
Because this thing pulls: you can happily let the clutch out just above idle and it'll cruise through traffic like a shark through a shoal of tuna.
There's more than enough torque for round-towning anywhere above 2500rpm, serious grunt above 5000 and a huge wave of power all the way from 8000rpm through to the power peak of 113.9kW at 12 500rpm.
After that delivery drops off quite sharply and there's no point in chasing the redline at 13 750rpm or the rev limiter at 14 200.
All of this is in A mode, of course. Like Suzuki's latest-generation superbikes the R1 now has three power modes, selectable at the flick of a thumb on the right switchgear, but operating on the "fly-by-wire" throttle rather than the engine mapping.
The top setting is harsh, choppy at small throttle openings and difficult to ride in traffic - but the instant response is addictive. The middle, STD setting gives you all the torque and most of the power but you have to twist further and wait longer for it, which makes it much easier to modulate in crowded surroundings.
ONE GLORIOUS AFTERNOON
The low or B mode turns the bike into a pussycat. Twist its tail as you will, it refuses to bite. Considering it rained for most of the time I had the bike, I was grateful for that - even the standard mode was a bit of a handful on streaming wet roads.
But we had had one glorious afternoon of crisp, clean winter sunshine and dry roads, the white R1 and I, non-stop hooliganising over my favourite roads, grudging the stops even for fuel - which is why the photos alongside are Yamaha's, not mine.
We stayed in A mode, howled four times down our 6km test straight, three times over the standard "ride and handling" section (just practising, Cyril) and even hoicked an unplanned wheelie on the National road pulling away from a pit stop.
Given the new engine's superbly muscular response, the bike's ultimate performance was mildly disappointing. I expected a bit more than a GPS-measured 281km/h at 13 200rpm but the bike was rock steady at that speed and seemingly happy to carry on cranking all day.
STANDARD YAMAHA ISSUE
It was also unexpectedly thirsty: three days of messing about in the rain and one afternoon of full-tilt boogie averaged out at nearly eight litres/100km. But then nobody's going to buy an R1 for economical transport, are they?
The rest of it was - dare I say it? - standard Yamaha issue. The latest version of the vertically-stacked, R-series gearbox with its shift mechanism right at the top, as far away from the oil level as it can get and still be inside the cases, is as notchy as ever, but firm and positive at high revs with a commendably short throw.
The long swing arm which is the cornerstone of Yamaha's chassis-design philosophy throws up the usual driveline lash and the factory's median suspension settings are, as always, much harsher at the rear than in front.
But the pinpoint steering and incredibly "planted" feel of the front end are also still there, giving the rider almost unlimited confidence to brake insanely late, turn it in with the brakes still on and get on the power early to use all that gorgeous "big bang" grunt out of every corner.
The rear suspension can be made to misbehave under provocation, especially on bumpy roads, but the front wheel just goes where it's pointed, every time.
The front brakes have Sumitomo's latest six-piston radial-mount callipers on 310mm floating discs. They lack the awe-inspiring initial bite of Brembo's best but come on with huge power that's easily modulated to change the bike's attitude in mid-turn - although it's worth noting than Yamaha's factory World Superbike machines still use Brembo.
The seating position is well forward, throwing a lot of weight on the rider's hands at low speeds but perfectly balanced for high-speed, cut-and-thrust cornering while the seat is high, wide and hard - although not quite the plastic plank of some previous R-series Yamahas.
The screen is fashionably low - I'm always amused that the first thing any racer does when preparing a modern sports bike for the track is to fit a higher screen - but the new fairing with its projector headlights and running lights inside the ram air intakes is both effective and very stylish.
The rest of the styling is a little fragmented, especially in the white and grey livery with purple frame of the test R1, but hangs together to minimise the bulk of the huge underseat exhaust canisters.
VERDICT
The first R1 was Yamaha's reply to the Honda Fireblade. Now the Big Bang engine adds an extra individuality, a distinctly different power delivery to the R1's superb dynamic package.
It's the most European of the Big Four superbikes; if you're in the market for a litre-class road rocket, ride this one last.
ENGINE
Cylinders:
Four.
Capacity:
998cc.
Bore x stroke:
78 x 52.2mm.
Compression ratio:
12.7:1.
Valvegear:
DOHC with four titanium overhead valves per cylinder.
Power:
133.9kW at 12 500rpm.
Torque:
115Nm at 10 000.
Induction:
Electronic fuel-injection with chip-controlled throttle and four 45mm Mikuni throttle bodies with variable-length intakes.
Ignition:
Transistor-controlled electronic.
Starting:
Electric.
TRANSMISSION
Clutch:
Cable-operated multiplate wet slipper clutch.
Transmission:
Six-speed constant-mesh gearbox with final drive by chain.
SUSPENSION
Front:
43mm inverted cartridge forks adjustable for preload with adjustable compression damping in left leg and adjustable rebound damping in right leg.
Rear:
Rising-rate linkage with remote-reservoir gas-filled monoshock adjustable for preload, compression and rebound damping.
BRAKES
Front:
Dual 310mm discs with Sumitomo radial-mount, one-piece six-pot opposed-piston callipers.
Rear:
220mm disc with Nissin single-piston floating calliper.
TYRES
Front:
120/70 - 17 tubeless.
Rear:
190/55 - 17 tubeless.
DIMENSIONS/WEIGHT
Wheelbase:
1415mm.
Seat height:
835m.
Dry weight:
177kg.
FUEL TANK / CONSUMPTION
18 litres, 7.9 litres/100km.
TOP SPEED
281km/h (measured)
SERVICE INTERVALS
5000km.
PRICE
R165 000.
RIVALS
R137 999 - Honda CBR1000RR
R149 995 - Kawasaki ZX-10R
R155 650 - Suzuki GSX-R1000
Bike from:
Yamaha SA