Six Weeks and Counting& ...
Six Weeks and Counting…
Yamaha’s all-new YZR-M1 four-stroke GP bike is entering the final development phase before its much-awaited race debut at the Japanese Grand Prix on April 7 2002, round one of the new-look MotoGP World Championship.
Following more than a year of intensive and successful on-track development, the machine is currently undergoing a final round of European tests before heading east for pre-race testing at Japanese GP venue Suzuka. The aim of the outings at Spanish tracks Valencia and Catalunya is to continue honing the bike’s impressive race-distance performance, so that Marlboro Yamaha Team riders Max Biaggi and Carlos Checa can give Mission One the best-possible start to its challenge for the first MotoGP crown.
The YZR-M1 is powered by an ultra-compact, in-line, four-cylinder engine. Weighing around ten per cent less than Yamaha’s YZF-R7 Superbike engine the M1 still produces in excess of 200 horsepower. The engine would be considered a work of art by many– the crankcases alone take over 20 days to machine from solid aluminium billet with the advanced manufacturing technology employed providing a better weight-strength ratio and making design modifications easier. Yamaha engineers reckon they could boost power output but that would have compromised usability, which has been their number-one priority throughout development. At this level of motorcycle racing more horsepower doesn’t necessarily mean faster lap times, quite possibly the opposite, in fact.
“ Ever since we started racing two-strokes in the then-premier 500 World Championship in 1973 we’ve realised that the best measures of a race bike’s overall performance are its drivability and it’s overall balance,” says Yamaha YZR-M1 project leader Ichiro Yoda.“ This is the concept we’ve stressed throughout development of the YZR-M1.”
Transferring 200-plus horsepower to the tarmac is never going to be anything less than thoroughly challenging, even for riders like Biaggi and Checa, so the factory has focused on creating engine/chassis interaction that communicates rear tyre feeling to the rider more directly, creates better tyre-to-tarmac contact and produces more efficient tyre performance over full-race distance. This is one reason why Yamaha chose from the outset to equip the YZF-M1 with carburetors instead of fuel injection.
The M1’s electronic-control, slide valve Keihin carburetors give the M1 very good drivability, both during acceleration and deceleration, and Yamaha engineers believe that a carburetor’s atomizing characteristics are still superior to those of a fuel injection system. Also, carburetors use natural pressure difference to suck fuel/air mixture into the engine, and most riders still prefer the user-friendliness offered by this function. We will, of course, continue development work with both fuel injection and carburetors to monitor if the fuel injection system will provide a significant advantage in the future.
The M1’s aluminium Deltabox chassis is a new design, though based around that of the YZR500 two-stroke which was generally acknowledged to be the sweetest-handling 500 GP bike. The use of an inline four-cylinder engine (rather than the V4 configuration employed in the YZR500) has allowed engineers to achieve excellent overall balance. The engine configuration also creates a compact bike with a simple layout for intake and exhaust systems. And the M1 chassis also possesses the balance of rigidity and flex that’s essential for success at the highest level, already encouraging fulsome praise from everyone who’s ridden it. Optimum engine position and ideal front/rear balance were fixed during tests last December, though the chassis does feature a huge range of adjustability to allow engineers to adjust its characteristics to suit different circuits and conditions.
Yamaha YZR-M1 Specifications
Engine: Liquid-cooled inline four-cylinder four-stroke DOHC, 5-valves per cylinder
Displacement: Under 990cc
Maximum power output: over 200 horsepower
Clutch type: Dry multi-plate
Frame type: Aluminum Deltabox
Fuel tank capacity: 24 litres
Weight: 145 kg (to FIM regulation)