Cycle News - Archive Issues - 1980's

except when it's being warmed up - a process that takes about a quarter of me time of a conven tiona l ~. air-cooled four-stroke. With 's uch a hot-running engine, mat is the reason for me new watercooled prototype engine currently under development, which will power not only me next-generation road bik es but also - to retain the r:- affinity between track and street 00 machinery which Le Raux deems Ci) ',importa m for marketing purposes .-4 an updated version of the RC588 ~ racer? .-4 "No, it 's not that at all," says .-4 . Crig hto n with a smile. "The 'on ly .... reason for water' cooling on a conventional engine is to prevent power loss through heat expansion and eve n tu a l seizure of the piston , V because the clearances are so tight ;> so as to get extra power. .O n the o rotary, you've got 16 thousandths side clearance on the rotor and since we don't have a piston as such, it's not a problem. We're making a water-cooled street bike because on escort du ties where they're doing about I0 miles at wa lking pace, some of the police bikes have an overheating problem which affects the carb urerio n, We could revamp the induction system , but it's easier to go to water-cooling especially as it means we can actually save a great dea l of weight - as much as 15 pounds, because we won't need any of me extensive finning on the rotor housing, which is actually extremely heavy. Even with me extra weight of th e radiator and water, we shall be able to get the racer to 275 pounds with no diffi culty. " When that happens, one can expect the already highly impressive performance of me RC588 rotary racer to become awesome, especially as Bria n Crighton and his small team have a winter of dyno testing in from of them, loo king to extract even more power from the barely-developed power unit. ' As it is, the rotary engine is a rider's de ligh t: thanks to its low 9.2: I compression (conventional fourstroke engi ne tu ni ng criteria such as ignition tim ing, mixture and compression are relatively unimportant on a rotary, which also cheerfully produce the same horsepower on un leaded fuel as on best racing fuel) it starts easily in JUSt a couple of steps and fires up instantly, with two three-lobe rotors immediately ready to perform. Clutch it quickly as she fires and roll th e throttle on hard to ca tch it, and yo u' re rewarded with a revcounter needl e spinning around in from of you like a gyro and a unique engine note from the long stainless steel exhaust. From trackside, me rotary is lik e a chameleon: at low revs it sounds like a two-stroke, spitting a little on the overrun into a turn and occasionally emitting a sheet of flame from the exhaust as presumably a bit of unvaporized oil or unburnr mixture ignites, while flat out down th e straight at high revs it sounds just like a four-stroke four- cylinder Superbike. On board the thing , however, you're comp letely unaware of this: you're too busy trying to recover from the astonishment of having no vibration of any kind at all , a responsive thro ttle that has the engine spinning around ever faster without you seemingly having done anything except think about cracking it open, and that incredibly wide spread of smooth, smooth power from practically zero till when the red line on the rev-coun ter tells you to change up. This turns a circuit like Mallory Park into a freeway, and the gearbox into semi-automatic: top ~ ~ lS S Z 20 (Left to right) Norton mechanic Dave Evans. test rider Malcolm Heath. and senior engine development engineer Brian Crighton , down the straight on the fivespeeder, back one for Gerards, top again down the back straight before coming back one for th e Esses , second through th e hairpin and chicane, then top down th e straight again. Try doing that on an RS500 and see where you get ! What's more, there's so much usable power almost everywhere you can shan-shift if you feel like it and let th e rotary pull you through without fuss or complaint - like on the way into Devil's Elbow, for example: notch third soon after the exit of the chicane, then fourth almost at once while you're still fairly upright, watch the revs drop as low as 5000 rpm as you , do so bu t without making any difference whatsoever to your rate of acceleration, and then crank right over hard into the · turn. If you cou ldn't do tha t, you'd have to change up while laid right over, which could unsettle the bike and anyway wou ld prove awkward with your knee scraping the tarmac. The gear cluster is a standard street one which because of th e nonexistent power bank has perfectly suitable ratios for the track, but is marginal on strength , According to Crighton, Hewland is making a new cluster for the water-cool ed bike, which will also hav e a dry clutch to liberate a bit of extra power and gear primary drive instead of th e ar chaic duplex chain, practicall y th e last remnant of th e o ld-style T rt a n a thinking in me rotary engine: this is a power unit for the I990s. It 's forgivabl e I hope to have co n centra ted exclusi vely on the engine so far, but an important pan of the weight-saving eq ua tio n is the twin spar aluminum chassis fabricated by Spondon for th e engine. Three weeks before my test th e bike didn't exist - hence the rather tatty fairing fitted for the track excursio n which had just come back that morning from the fiberglass shop' where it had been having a mold wrapped around . it. I'm afraid it shows in the way the bike handles at present: both front and rear suspension felt much too stiff for my taste, and the way it hopped and skipped in the air around Mallory's ever-increasing bumps, it will cer- ' tainly need some serious development before it can be considered rideable in the Isle of Man, for one. But with the from end straight off an RG500 Suzuki and an Ohlins suspension unit holding up the rear, that can on ly be ' a matter of tria l, error and time, However, I must say that I think the bike is bigger than it ought to be, a fault perhaps occasioned by the fact that test rider Malcolm Heath is a six-footer like myself and with even longer legs. With an engine mat is so physically small and light, Norton should be looking at making a sort of modern 350, a bike with the performance of a 500 and me size if not the weight of a 250. Maybe me water-cooled bike will achieve this, but at the moment it's a bit rangy to look at and sit on. I also thi nk Spondon must swallow their pride and fit Ap·Lockheed brakes o n the thing: sorry, but the Spondon four-piston calipers and 310mm discs give a very strange feeling whe n you gr ip the front brake lever: they seem to work only grudgingly, and do n't inspire confi dence. Si nce you have almost no en~i ne braking as suc h, apart fro m a slight servo effect in reverse when you shut off the engine, ra th er l i ke an electr ica ll y-a p p lied tra nsmission brake on a truck, good brakes are a vital requirement on the rotary, and th ese' weren't brilliant. The chassis, however, felt good in turns, was easy to flick from side-to-side in the ch icane and generally inspired confidence - so long as you didn't hit a bump: then - hold on tight! -T he engine by contrast has practically unlimited ability to please the rider, though it takes a few laps to realize how to get the best from it. To stan with, you have to learn to keep some power applied at all tim es, even in a tight chicane or hairpin, because otherwise you run the risk of stalling it altogether, as I did my first lap at the hairpin. So you have to drive into a corner, or else at least flip-nap around with the clutch in and blipping the throttle. In other words, ride it like a two-stroke, with the important difference that you don't need gobs of clutch on the way out to make the bike acce lerate properly: just crack the throttle open and leave the rotary to do the rest. It also likes a good bl ip on the throttle when changing down through the gears, and it seemed better to do this one gear ai a time, rather than two or three at a time like on a two -stroke. T he only time I got the rear wheel hopping was when I used bottom once inadvertently for the hairpin. After a while, you learn to adapt your 'style to the engine's unique character, and you' ll have no real problems. O nl y mi nor thing to watch OUt for is that the rotary doesn't really like part-throttle openings, when it tends to lurch and hunt a bit because it's not under load. However, that's not normally a factor on a race track where you're either all on or all off me throttle or nearly so, and the long, long sweep of Gerards Bend at Mallory must be one of the very few places on a British circuit where you 'd encounter this small idiosyncracy. The Isle of Man might be a different matter, but we'll have to wait and see about that. . Indeed. because next year -th e Norton is bound to be headed to the Island where the factory's return to the TT -15 years after they last won a race there (Peter Williams' victory in the '73 F750 event on the monocoque John Player Norton) is bound to be a focal point of TT Week '88. Bu t where else they race next season depends o n the o u tcome of a con- . tro versy surrounding th e bike whic h Brian Crigh to n is eager to resolve before m e project advances m uch further. T he British ACU rate the bike's cubic capacity as twice its swept volume, which wi th two rotor chambers of 294cc, equals 588cc he nce the racer's R C588 model designation. But wi th a factory of two applied to this, that means me bike is rated at I 176cc. and the ACU - who Crighton says have been singularly unhelpful in resolving this difficulty: can you imagine what would happen if it were Ital ian, or Spanish, or Japanese?! - simply say they are applying an FIM formula and sorry, mat's all there is to it. If that's the case - and Crighton has yet to see the FIM ruling in prim - it's very .cu rious, because while rotary engines may be new to motorcycle racing (well, I do n 't think many people took Suzuki RE5s to me trackl), they are far from such in the .ca r world. where Mazda-powered ·machines have a lon g history of success fu l competition, winning th e Index of Performance in the Le Mans 24 H ou rs severa l times. for example. T he FIA, governing body of car rac ing, ra te a rotary's cubic capacity as 1.1 times its swept volume , and though Cr ig hton wou ld obv iously prefer a I:I formu la , this would seem to be mu ch more realistic than a 2:1 ruling as presently applied. Thiswould give the RC588 a cubic capacity of 823cc, which would enable a slightly smaller engine to compete effectively in the 750cc Superbike and TT F-I classes, especially as Le Raux plans to produce a top of the range water-cooled street bike based on the single-seat racer . which would be Norton's answer to the RC30 Honda, Ducati 8V/ 851and the like. In the meantime, where else the bike will race in 1988 beside me 10M is under review while this issu e is thrashed out. I promised myself at me stan of this story that I wouldn 't stamp the rotary Norton racer as Britain's Great White Hope for future racing success. After all, it 's still so new, it's only competed in a couple of relatively low-key British races as part of its development program so far , and there 's a lo ng way to go. Bu t ho nestly - the bike has so much promise, so m uch potential, it's hard n o t to be enth usiastic abo ut it, espec ia lly .after having ridden the thing. Yes, the Norton does exist, it has already attained a very acceptable level of performance, and you have to take i t very seriously, especially with a man like P h ilippe Le Ra ux behind it. Maybe Honda better dust off the p lans for their own rotary racer and take a second look at it! •

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