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/128152
THE PROS AND CONS OF THE MIXED ERA. By MICHAEL SCOTT PHOTOS BY GOLD & GOOSE T he four-strokes won at Suzuka. That we now know - and they did it fairly easily. It might not be the same everywhere, however. And detailed analysis shows why. The new MotoGP four-stroke bikes and the old 500s are very different in the way they perform. The story all season long is going to be the feisty two-strokes versus rorty four-strokes. Yet they can match lap times in practice as close as paint - at least at the moment. That's after almost 20 years of solid race development for V4 twostrokes, against four-strokes in their Suzuka, corner by corner, with Kenny Roberts Jr. TURN ONE/TWO - third/second gear "These are taken as one comer, with a late apex," Willing said. At the braking point, the twostroke is at 180 mph, the four-stroke at 184. At the apex, however, the speeds were almost identical, the two-stroke just 0.62 mph faster at 70.68 mph. The two-stroke apex was marginally later - but that could be a factor of carrying a heavier fuel load on that particular lap. TURNS THREE/FOUR/FIVE: THE ESSES - second gear The next section is a series of flip-flops taken in second all the way. The bikes are still neck and neck - in a way. In fact, on this lap, the two-stroke was quite a big quicker on arriving at the comer - 112.84 mph against 110.36 - and marginally quicker at the apex of the first two bends (87.54 to 85.56 and 79.98 to 79.36). On the final Ess, it was the other way around, the 990 [four-stroke] at 84.32 mph and the 500 at 83.7. The result is that the twostroke had reclaimed the speed lost from the start Hne and down the straight. It's beginning to look like it might pull away. But not so... TURN SIX - second gear Comparison becomes difficult at this point, because the next comer is the changed Dunlop Curve, with a slightly different entry line and speed, affecting the exit from Turn Six. This is probably why the 2000 two-stroke apexed at 81.84 mph, and the 990 at 77.19. But Kenny's new ability to square the comer off more is also significant. The end result is interesting. At a particular bump before the now-changed point of closing the throttle, the lap times so far are now identical. But now, the first technical to-and-fro section completed, the four-stroke starts to come on strong. TURN SEVEN: DUNLOP - third gear This reprofiled tum, around 4.34 mph slower (apexed at 89.28 rather than 93.62) and 128.7 feet shorter than previously, accounts for half-a-second improvement. It also means a slightly slower entry onto the short straight that follows, which is very good news for the fourstrokes... for it is here that their power begins to tell. DEGNER ONE and TWO - second and first gear The double right-hander continues the trend of slightly slower apex speed for the 990: 93.62 against 95.23 at the first apex, with an even greater difference at the second apex, 68.88 mph against 63.42. But there follows another surge of medium-speed acceleration under Suzuka's underpass that gives the track its unique figure-eight configuration. By the time the throttle is closed for the hairpin, the 990 has started to gain. Although the second apex was taken at only 63.42 mph compared with the two-stroke's 68.88, the four-stroke has hit 138.88 mph at shut-off, and the two-stroke only 134.54. 48 MAY 1, 2002' c U a I • n e _ s: first-ever race. It's obviously not going to last. Comparing them inch for inch, corner by corner, and on lap times, it's amazing just how close they are. The two-strokes are faster mid-corner, and at lower speeds their better power-to-weight ratio gives them an advantage in initial acceleration. Kenny Roberts Jr. leads Alex Crivill~ last season aboard his Suzuki RGv500 two-stroke. From third or fourth gear onward, the 10 or more extra horsepower of the four-strokes starts to take over. Then the new bikes gain time and distancein chunks ... in much the same way a HAIRPIN - first gear Again, the older bike is a little quicker at the apex - 37.82 mph for the four-stroke, 40.17 for the 500. This highlights another difficulty this year with the switch to Dunlops ... "The current front tire is not as good as last year's Michelin," said Willing. TURN ELEVEN/TWELVE - third/fourth gear A double-apex right taken under power while hauling the bike to the right for the approach to the long, looping and crucial Spoon Curve. By the time the throttle is closed for the Spoon Curve, Roberts has gained four tenths on the new bike compared with the old, "most of it on acceleration out of the hairpin." SPOON CURVE - second gear Long double-apex right is crucially important because it leads onto the main straight. Exit speed gained here pays big dividends to lap time. Once again, the old bike's relative lack of mid-range was costly. Kenny ran through the first apex slightly slower on the two-stroke, 81.22 mph to 83.7... the first time on the whole lap, the four-stroke had a higher corner speed. The reason was his line aiming for a faster second apex on the two-stroke to compensate for its inability to square the comer off and squirt out. The two-stroke had gained a fair bit of speed at that point because of this technique, 70.68 mph to 68.82 for the four-stroke. Importantly, however, the four-stroke throttle had been opened a full seven tenths of a second earHer for that sliding surge onto the straight. BACK STRAIGHT - sixth gear Four-stroke territory. The difference in acceleration out in second gear is not so great; because the two-stroke's better power-to-weight is still in play. By the upshift, the two-stroke is doing 92.38 mph at 11,653 rpm, and the four-stroke 96.1 at 11,840 rpm. The four-stroke has a slightly larger throttle opening - 71 percent to the two-strokes 64 percent. But it is third gear that counts, now at full throttle for both types. The new bike gains 5.58 mph 1n that one gear alone. From there on, the acceleration graphs run almost in parallel, but with the fourstroke carrying that advantage aU the way down the straight, to peak at 185.31 mph, the twostroke just catching a little at the end at 181.9. On other laps, however, the four-stroke had achieved a higher speed, with Kenny's best in practice being 187.42 mph. Willing pulled up the calculator to compare the speeds. "All other things being equal, it computes to a difference of about 11 horsepower in favor of the four-stroke. That's about right," he said. "But it's probably double thalin the mid-range." 130R - fourth gear One of the world's epic comers, and an equalizer for both types. Again, the 500 carries a little more spe.ed, 111.35 mph against 110.36. The four-stroke bas it back again at the point of shutting the throttle for the chicane - 145.08 mph against 144.46. CHICANE/START-FINISH STRAIGHT - first/sixth gear The slowest corner in radng, with the same sort of difference here as elsewhere, the twostroke apexlng at 38.06 mph, and the four-stroke at 35.96. Then another burst of fuU-throttie acceleration, and though the two-stroke has an early advantage, the power of the four-stroke soon overcomes it. By shut-off time at the end of the straight, the four-stroke has gained another three tenths of a second and is traveling at 184.76 mph compared with 180.17. Job done. Lap time won.