Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128099
2001 Grand Prix Road Racing Series: The End Of An Era Things have changed a lot since then, especially in the last five years, with radically improved tire life and performance. The four-strokes now face the problem that the two-strokes have solved - an excess of power and slightly more weight mean they're going to need a whole new generation of tire development, according to Dunlop's racing boss Jeremy Ferguson. It is not only the tires that have changed. So too have the engines. Two-stroke critics have been calling the current racing V-fours dinosaurs for a long time, with the justification that the Honda NSR has (until this year) barely changed since 1992, and much the same goes for the other bikes. "But there must have been some development," points out McCoy's race engineer Hamish Jamieson. "Because the lap times and race averages keep getting faster." The major thrust of that development has been devoted less to raising overall power, since it was already considered enough, but to making it easier for the rider to use that power. To the extent that the Honda NSR in particular has become so amenable that it is a GP winner for everyman. With Doohan's genius forcing the pace nobody else got much of a look in. Since he's gone, the likes of Alex Barros and Loris Capirossi have been able to jump right on the current NSR (from a 250, in Capirossfs case) and win races. Now these rather marvelous racing machines are bound for the dustbin of history, it seems. The 2001 V-four factory bikes are refined, rideable, rampant... and redundant. What was the point of all that development? The breed of sporting "I wouldn't want one if I'd been able to use a footbrake," he growled. The point is that two-strokes had their own quirks, and the greatest riders found ways to use them to their advantage. Then all the others had to learn that trick, in turn obliging the champions to find new ones. Until we arrive at today's generation of highly educated and highly developed twostroke riders. Are they too highly educated? Too specialized? Opinion from the sidelines does not support this view. Several (though famously not all) Superbike riders have found it impossible to make the shift in technique from four-stroke to two, but going the other way is historically pretty easy. If you're good enough to ride a 500 two-stroke, well, then you can ride anything. That's easily said, however, but perhaps not so easy for a rider to believe, especially if he is feeling ever so slightly insecure already. Which means pretty much all of them: toplevel sport of any kind is no place to look for well-adjusted individuals. So let's assume that all of them harbor secret fears that this might be their last chance. Which adds another spur to the season. A straw pole of the top guys last year revealed mixed feelings about future prospects. Rossi, riding high on the two-stroke and fresh from his first-ever ride on a four-stroke race at the Suzuka Eight Hour, was dismissive of four-strokes. "Very easy to ride. I prefer twostroke. It make a better noise. And it's harder to ride," he said then. His father, Graziano, listening in, couldn't resist a "wise words" interjection. "Not so easy to ride, Vale, if it has 230 horsepower and less than 150 kilogrammes [330 pounds]." Biaggi has recently softened his strong view that all real racing bikes are two-strokes; Kenny Roberts Jr., pragmatic and down-to-earth, opined he'd be happy to ride whatever type of machine was going to be more competitive. That, of course, remains to be seen - but there's a strong feeling in the paddocks that the 990cc fourstrokes are going to be pretty damned competitive right out of the box (Honda's NR500 may not have been successful, but it wasn't a million miles away, with the same cubic capacity). This has left the die-hard two-stroke fans relying on one last thing to keep them competitive tires. This is a true irony. The biggest thing about the two-strokes, for most of their racing life, has been the way the snappish throttle response chews up tires; one of the biggest single advances came when Honda turned their V-four into a c1ose-firing-order "Big Bang" engine - purely because it saved tires. 28 APRIL 11, 2001 • .. Y .. I The man many believe is capable of bringing results to the Proton (nee Modenas) team in 2001 - Jurgen van den Goorbergh. • ne_s From J984 until today, if you wanted to win a 500cc championship, you needed to bring a V-four two-stroke. It is a clear example of an evolutionary process arriving at the most effective package of engine architecture. In fact. of parallel evolution, since there are actually two completely different types of V-four. The first is more correctly a U-four, or a sort of squashed-out square four. The design used by Yamaha and Suzuki has two crankshafts, one behind the other and geared together to counter-rotate (handily negating torque reaction). The cylinders are splayed at a little more than 60 degrees, keeping the weight low while making space in the vee for the airbox, carburetors and reed-valve induction blocks. The top exhausts take a nice, straight run out under the seat and the lower exhausts are not much worse off. It's a neat package that betrays its roots - a pair of 250cc twins linked together. Yamaha's first 500s had the twins side by side. to make a straight four; Suzuki followed a design from the smaller classes where they put one pair behind the other one. This square four was highly influential, winning seven manufacturer's titles as Yamaha persisted with their straight four before also switching to a square four. It was Yamaha who first put the cylinders in a vee, in J 983, to allow the carburetors to be tucked away - though at that time they still used rotary disc-valve induction, the valves driven by skew gears to run at 90 degrees to the crankshaft. It was Honda who brought in reed-valve induction, which might cost a little in horsepower, but paid huge dividends in broadening the power band and improving throttle response. That was with their V-three of 1983. One year later they joined the V-fours, with a typically different design. This was a true V-four, with a single crankshaft. One advantage was a reduction in the number of main bearings needed, disadvantages included severe torque reaction to sudden rev changes, and greater overall width. A balance shaft introduced in the late '80s reduced the torque reaction; a quiet switch to two separate crankshafts came in the last five years. But it is still essentially a singlecrank motor, but with a two-piece crankshaft, which made manufacture easier and improved durability. It was MZ's Walter Kaden who discovered the potential of the two-stroke engine, by harnessing the pressure waves and exhaust resonances. It was the racing regulations that limited 500cc engines to four cylinders. It was engineering common sense, along with some creative copying, that led to the V-four. And it is again racing regulations that have brought the design to the end of a glorious road. two-stroke died out with those last GP replicas from Suzuki and Yamaha of the '80s, so I'll claim old-timer's privilege to tell you what you missed: those smokin' street strokers, from Suzuki's whacky water-cooled 750 triple and Kawasaki's completely mental air-cooled ctitto to those final 500 GP replicas from Yamaha and Honda, both topped by Suzuki's faithfully copied RG500, were just staggering. Until they were killed off by corporate cowardice in the face of pollution problems that most engineers will tell you are far from unsolvable. And gone with them a type of engine - light, compact and mechanically simple - that was ideal- Iy suited to motorcycles. Manufacturers have espoused four-strokes for better or worse, and now they have acted in concert to steer racing the same way. Maybe history will prove that the titans weren't wasted .. All that hardwon knowledge of resonances and shock waves, of exhaust power valves and induction reeds, and all the things that have made the current bikes so conspicuously user-friendly may yet return, perhaps in a different form. Two-strokes aren't dead, claim fans. Only sleeping. By contrast, their last racing season as unopposed kings of the track is set fair to wake the dead. eN