Back in 1996 Kunihiko Miwa was attending the launch of the Yamaha Thunderace. A worthy bike, if a bit porky and uninspiring. At the time Miwa decided he wanted to build a bike with a philosophy of 'no compromise.' This he did, by coming up with the YZF-R1, a bike which was to do something that the Thunderace never did - knock the FireBlade from its perch as king of the sportsbikes.
For 2002, the R1 has a new project leader - Yoshikazu Koike - and it's his job to keep the bike true to Miwa's philosophy, but make it better still.
Not such an easy task, because as every year passes we become a more demanding lot. Sports bike owners need to be as happy cleaning their machine on a Saturday as riding it on a Sunday. Sports motorcycles now need to do so much more than go fast - they've got to look good and go good. Also, many of us are realising that we want more than outright power, we want something a bit better balanced, with useable as opposed to brutal power. Honda knows this, after starting to head down this route with the FireBlade. Yamaha also knows this now, and that's what they wanted to accomplish with the 2002 YZF-R1, so here it is in all it's glory.
First of all, look at these pictures. This is a bike which will make you feel good to own. While its competitors such as the Blade and ZX-9R have changed their looks dramatically over the last few years, the R1 has remained true to its original, lupine beauty. Look closely at the 2002 machine and you can see that these looks have been refined, and that the designers have moved things on. Yamaha designers, it seems, have taken a leaf out of the pages of the book of Ducati: 'Why break what's already fixed?'Those elliptical, almost organic eyes form into the trademark R-series stare.
The bodywork now has huge cutaways, exposing the naked muscle of the motor, but it still hugs the engine and frame, before disappearing into a thin, wasp-like tail, which now has super-trick LED rear lights and an undertray which neatens up the rear end. Yes, it's hard to believe, but if you compare the 'old' 1998 R1, then you'll find that the new 2002 machine makes the first model look just a little bulbous and, well, a little old. Colours for 2002 are simplicity itself. No shell-suits here, instead you have the almost quicksilver-like silver and satin black you see here, red and black or blue and black. For the traditionalists among you, there's also the old Yamaha 'speedblock' option, which has to make an appearance as it's the corporate colours in the States.
Underneath the skin and the story is the same. Things look very similar to the older machine, but they do have some very important differences. The foundations and architecture of the motor remain from the original bike - 998cc, 74 x 58mm bore and stroke, 11.8:1 compression ratio, five valves per cylinder, two inlet, three exhaust (you only really need four valves, but 20 looks nicer than 16 in a flashy graphics font on the fairing...) but certain changes do make this motor special.
First up, the fuel-injection system. It's different from most systems in that it incorporates what they call a 'suction-piston-type' EFi system. Kenji Abe, was responsible for engine design, so we'll let him explain: "This system allows an ideal air/fuel mixture in low rpm-range by controlling the air intake. It does not require complicated electronic controls and it combines the advantages of a carburettor with those of today's fuel injection. In other terms you can say it is a fusion of analogue and digital." The vacuum controlled fuel injection system combines the 'analogue' response feeling of a carburettor with the 'digital' precision of fuel-injection. This system uses a free suction-driven valve piston to regulate air intake flow independently from electronic control. This ensures the optimum air volume without a clever (and expensive) electronic brain doing the work. But, a microcomputer control collects data from various sensors to ensure an optimum fuel supply with the right air/fuel mixture. To get things working correctly, Yamaha used two experienced players in this field, Mikuni for the throttle sensor and Mitsubishi for the ECU (electronic control unit).
So, simply put, it seems that Yamaha seems to have added the vacuum operated slide from a CV carb to a normal injection throttle body. This means that no matter how aggressively the rider opens the throttle (and so the butterfly) the slide governs the rate that the air enters the engine and hence the torque produced. Net result is that with some fiddling with the slide springs and slide damping holes (the bits a Dynojet kit messes about with in carbs, but for different reasons) you could probably modulate the way the bike 'picks up' on the throttle.