Moto Tour – September 24: early morning wake-up call! –

Posted on by admin

Hercules W 2000, Norton Classic, Suzuki RE5 and Van Veen OCR 1000

The fascination of rotary engines

Content of

The concept of the rotary engine was brilliant, but unsuccessful. MOTORRAD Classic was on the trail of the myth and experienced the fascination in the saddle of the four most famous Wankel models: Hercules W 2000, Norton Classic, Suzuki RE5 and Van Veen OCR 1000.

Everything turns, a muffled hum and roar penetrates the skull. No, this has nothing to do with the excessive consumption of spirits the night before, but simply with the fact that four representatives of the rare species of motorcycles with rotary engines are ready to go. What rotates are the “pistons”, i.e. the trochoid or also called runners, instead of whizzing up and down as in a reciprocating engine. This in turn leads to its very own sound, a uniform hum, and with increasing speed also tubes. There weren’t many rotary motorcycles for sale, even if various companies bought the license to rotate. So does Fichtel & Sachs, where they thought of their use in snowmobiles and as stationary engines. It was also used in motorcycles that were to be built by Hercules in Nuremberg. The development of the W. Started in 2000, in 1970 a first prototype stood at the IFMA in Cologne. In 1974 the final version went into production, making it the world’s first Wankel series motorcycle.

Hercules W 2000, Norton Classic, Suzuki RE5 and Van Veen OCR 1000

The fascination of rotary engines

W 2000 more comfortable roadster than athlete

The W 2000 can be set in motion with little speed and pulls evenly and more powerfully than a two-stroke engine of the same “displacement” class. The draw wedge drive lives up to its name – pulling with the whole foot is the trend, the distances are typically long and contemporary. The moped history sends its regards, as in the form of so many details. The look at the VDO water clocks with the fidgeting, more or less randomly moving hands and the simple ignition lock with the 08/15 ignition key awaken memories of the blissful 1950s. After all, at that time one would have wished for such a motor that pushes out so evenly from below and so powerfully through the middle. The maximum output is at 6500 rpm, but this is where the red area begins. But the W 2000 is reluctant to turn that high today, and we don’t want to push it to the full for now. In any case, the character of the W 2000 is less of an athlete than a comfortable roadster. The man’s driver’s posture behind the wide, high handlebars and with the relaxed, bent legs also go well with this. The machine, which weighs 176 kilograms, has the potential for brisk cornering because it can be thrown from one lean angle into the other so easily.

The road should be flat, however, because the once praised Ceriani fork hardly or not at all speaks, probably due to the long service life, and unwillingly bucks over patches and cross grooves. The rear Girling struts are hardly inferior to it here, they pass on dry bumps just as dryly. Even the once-praised straight-line stability has to be classified as manageable, but nervous today. The front, hydraulically operated disc brake decelerates properly, but by no means brutally, the rear drum helps as best it can. While the Hercules still looked like a prototype that only accidentally went into series production due to some adventurous constructive solutions (primitive frame arm here, thin strut there), it makes up for it with its light-footedness and honest strolling when driving. So even when you stop at traffic lights you can ignore the fact that idling is practically never to be found when the vehicle is stationary and the control lamps are not at all visible in daylight anyway. The decisive factor, however, is the smooth running of the engine and the ample torque curve.

motorcycles

On the move: Hercules K 50 SE, Kreidler Florett RS

Race performance

read more

Rearview mirror PDF: Hercules-Wankel W 2000 (MOTORRAD 12/1973)

Norton Classic in the service of the British Police

In terms of running culture, the British representative of the quartet seems hard to beat. Regardless of the speed, the air-cooled twin-disc rotary engine of the Norton Classic displays the finest British manners. Even if his roots are of course German. BSA once installed the Sachs single-disk rotary gear in a chassis of the single-cylinder Starfire model. Based on the positive experience with it, a cooperation with Norton was used to develop the twin-disc Wankel with a chamber volume of 588 cm³. From 1984 about 350 copies were already in service with the British police and provided plenty of experience. So it was finally decided in 1988 to sell 100 copies of a civil, uncovered version to private customers – the Norton Classic. Basically nothing had been changed on the engine, only the sealing problems were solved by the Norton engineers by using the sealing strips from the Mazda Wankel sports car. And the problems with the high temperatures were eliminated at Norton with a trick: the intake air is enriched with fresh oil before it enters the Amal carburettor, the mixture cools the needle bearings and the inside of the shaft that carries the rotating rotors.

Does the comparatively compact, almost petite-looking British woman keep what looks and key data promise? After all, there is talk of 85 hp at 9000 rpm. The rider sits enthroned above the action, sitting more on a very soft, almost too spongy seat bench than sitting in the motorcycle and enjoys the arrangement of an active naked bike – not too upright, not too sporty. The lovely curved roads through idyllic British counties are already spreading before the driver’s mind – James may start the engine now. Okay, in the absence of a butler, the right thumb jumps in and the starter turns the engine into life. So there it is, the praised running culture. Nothing vibrates here, and the 588 willingly hangs on the gas.

Rearview mirror PDF: The new Norton Jubilee 250 cc Twin (MOTORRAD 24/1958)

Naked bike

Driving report: Norton 961 SE

The Norton Commando 961 SE in the test

read more

wolf

These bikes are certainly not for everyday use, but they don’t have to be.

The clutch and gearbox behave politely and inconspicuously, i.e. smoothly and precisely, with the gears engaging honestly and clearly. There are five of them, and after a few kilometers it becomes clear that you only need the first four to drive off and in town. Even as the proverbial turbine and with sovereign torque, the British glides through the rev range, increases evenly, perhaps a bit more energetically from the 3000 mark, in order (theoretically) to dash forward greedily to the limiter at 9000 tours. But I don’t really need or want to turn the Norton Wankel that high. Full thrust at medium speeds makes the Classic a stress-free, yet fast roadster. And the subtle, throaty bubbling when stationary is transformed into the wonderfully squeezed roaring like a BMW sports boxer, especially at medium speeds.

You only notice that she weighs well over 230 kilograms when you push it, while driving, the British woman turns out to be a light-footed, only slightly top-heavy looking lady who demands a little force when turning. She masters long curves and fast straight-ahead driving with natural, stoic stability, the Brembo brakes can be precisely controlled and decelerated appropriately effectively. The Marzocchi spring elements spring and dampen cleanly without appearing spongy, a good compromise. Overall, a motorcycle that one would have wished for a future and larger numbers.

Meticulously adjusted Suzuki RE5

That certainly also applies to the only Japanese woman who made it into series production – the Suzuki RE5. Suzuki had the courage to bring the bike, which was presented in Tokyo in 1973 as the RX5, to series production and to present it as the RE5 at the IFMA 1974. Great technical effort should improve the smoothness and performance of the single-disc Wankels with 497 cm³ – a blessing and a curse at the same time, because self-screwdrivers and even Suzuki mechanics were often overwhelmed even with adjustment work. Suzuki had opted for the circumferential inlet (others preferred the side inlet or a combination of both) – with advantages in terms of performance, with the disadvantage of uneven idling and poor smoothness in the lower partial load range. So one tried to remedy the problem with a special ignition system and a two-stage carburetor. In the partial load range and in coasting mode, only every second mixture charge is ignited, whereas every one at full load. In the carburetor, the first throttle valve (18 millimeters) opens controlled by the accelerator cable, the second (32 millimeters) only opens when a certain negative pressure is reached under load. In addition, an accelerator pump, a membrane-controlled enrichment and a shut-off valve are at work – the nightmare when making adjustments.

However, when driving, it turns out that the effort was worth it. The RE5 brought by owner and professional mechanic Burghard Schorstein is meticulously adjusted and in top condition despite its impressive mileage of over 74,000 kilometers. And she expresses this with the most gritty expressions of life of all four Wankel representatives. Dull, sonorous sawing with a powerful bass and a mixture of two-stroke and four-stroke timbre: This is how a three-cylinder two-stroke engine with a displacement of two liters should have sounded if it had ever existed. The RE5, which weighs 260 kilograms, looks massive even when standing still. Can the 63 hp break something? In fact, the Suzuki seems quite heavy when maneuvering, but the first few meters of drive completely reverse the impression. High up in the saddle you sit upright, your hands stretched out towards the wide and high handlebars, with your legs supported almost at right angles – a more gentleman’s posture is hardly possible.

Anyone who has such a Suzuki does not give it away anymore

The view of the foldable cockpit, known as the "botanical drum", is intoxicating with a flood of lamps and displays and even provides information about the gear that is engaged. The impression that the engine leaves in terms of steam from below and pressure in the middle regions is surprising. From idle there is useful power, maybe not quite as powerful as with the Norton, but the brave puller turns into an energetic puller from around 3500 rpm. Here the ignition and the carburetor seem to open all the locks and give free rein to the performance, an almost sporty bite emerges, which tempts you to exhaust this kick again and again. Too high speeds do not lead to a significant increase in performance, timely shifting in the hard and dry engaging transmission makes more sense. Unless you want to savor the angry roaring sound, which then reminds a little of high-revving British twins.

The amazing handling of the chunk can be savored on a brisk ride. "The rotor rotates against the direction of travel, that will probably compensate for the gyroscopic forces of the wheels and ensure great maneuverability," speculates the expert Burghard. In any case, the effect is noticeable, angling in an inclined position is as easy as with a 350. No wonder, the RE5 can be chased so courageously along winding country roads. The chassis, based heavily on that of the GT 750, lasts for a long time, even if the phrase "too hard at the back, underdamped at the front" seems to hit it quite well. I can live with that, but rather the blunt front brake, which also requires high manual strength, and the all too toxic drum brake at the rear. Nevertheless: Even if the maintenance can be horror, driving is a pleasure. The balance sheet for Suzuki is still sobering: of the approximately 26,000 RE5s built, barely 6000 were sold, a rumor has it that Suzuki sank the rest in the sea. In Germany only 66 copies were sold, and whoever has a RE5 today hardly ever gives it back.

Van Veen OCR 1000 with 135 Nm at 2500 rpm

This also and especially applies to the Van Veen OCR 1000. Only 39 copies are said to have been sold, five of them with the massive fairing. The then Dutch Kreidler import Hendrik van Veen once set himself ambitious goals: “We want to build a motorcycle that can withstand all demands and criticism.” A rotary engine seemed ideal as an engine: vibration-free, small, compact. And strong. For this reason, the choice was made for the twin-disc Wankel with two times 498 cm³ chamber volume, which was once developed by Comotor – a cooperation company founded by Audi / NSU and Citroën Use came. But Comotor soon slipped into the crisis, only 50 engines they had delivered by then. With 100 hp, the 1000 should have enough power, allegedly up to 130 hp were possible without any problems.

The equally noble and expensive bike shone when it was launched in 1976 with superlatives and technical finesse. The two rotors are hollow and are cooled by the oil flowing through them, hence the abbreviation OCR, which stands for oil cooled rotor. The combustion chambers are fed by a Solex double downflow register carburetor with an automatic starter and accelerator pump, the spray supply is guaranteed by an electronic fuel tap – goodbye to fuel tap fiddling. Also of the finest quality is the maintenance-free, computer-controlled Hartig ignition with 128 pre-programmed ignition timing angles, from which the optimal one is called up depending on the engine speed. A four-speed gearbox seemed to be sufficient, given the incredible torque of 135 Newton meters at 2500 rpm. A low-maintenance cardan takes over the drive, a double homokinetic joint is supposed to prevent annoying drive reactions. The 42-inch Koni fork with gas damping is responsible for clean front wheel guidance, while three-way adjustable Koni dampers are used at the rear. Brembo brakes, Ronal cast wheels – the list of high-quality components seems endless.

wolf

These four Wankel motorcycles leave a lasting impression.

The tension rises as I climb into the saddle of the 345-kilogram colossus. How does the dream of the perfect motorcycle, turned steel, drive, this exclusive rarity that I once sneaked around in awe as a teenager when I first saw a specimen in the wild? The first impression is huge. Even reaching for the handlebars and making the slightest maneuvering attempts make the weight inexorably noticeable, which seems to be concentrated in the steering head. Because of the fairing, a narrower, fairly straight handlebar is used than in the naked version, which doesn’t make things any easier. So press the button, enjoy the smoothness of the 1000 and engage the hydraulic clutch, give the bull a run.

When driving slowly, the OCR needs to be carefully kept on course, turning in is difficult, the high center of gravity requires concentration. The Van Veen pulls off gently but forcefully, let’s say 1500 rpm. The idle speed is a bit restless, the engine sputters a bit downstairs – rotary engines don’t like the fussing around for the photos. So gas and blow a little free – like the proverbial electric locomotive, the big green pulls the driver’s arms out. Unspectacular, rather inconspicuous quickly. High speeds seem unnecessary, I switch to fourth early and only a glance at the speedometer reveals what is barely noticeable: how, already 130 things? The subtle, pressed roaring engine sound does not reveal how rapid the acceleration really is. 4.2 seconds from 0 to 100 km / h were once measured – credible and respectable for such a heavyweight.

Crouching is not a solution

It’s not completely gone, the cardan-typical hardening of the hindquarters and the slight up and down during gas changes. But it remains moderate. On the other hand, the airflow that hits the driver’s helmet directly is quite coarse. Crouching is not a solution, because the view through the window is extremely cloudy. The posture on the 1000 is also not optimal, slightly leaned forward in a sporty way, but with unusually widely spread calves, especially the right foot does not find space on the footrest mounted far outside. Approach the first long curve carefully and take off the accelerator early, oha, I thought so – the load is clearly pushing out of the curve and wants to be forced around the corner with force and pressure on the handlebars. When braking, the right hand must grip properly. Effect, yes, quite okay – bite, no. To do this, you have to certify that the spring elements respond adequately and that they spring and dampen quite well.

The Van Veen is not made for road heating, but rather for very confident gliding over long distances. The consumption? Always in two digits. “It’s almost never less than 14 liters,” says owner Toni dryly. Eh don’t care. The Van Veen is certainly not for everyday use or for perfectionists – which more or less applies to all four rotary motorcycles. But perfection can easily get boring, and it’s often the real types and characters who are the most fun and leave the most lasting impression. It is a pity that the Wankel did not prevail, and may the few surviving specimens rotate for a long time.

Hercules W 2000

wolf

In 1974 the final version went into production, making it the world’s first Wankel series motorcycle.

engine
Air-cooled single-disc rotary engine, compression 8.5: 1, Bing constant pressure carburetor, Ø 32 mm.

Torque: 33 Nm at 5000 rpm
Chamber volume: 294 cc
Power: 27 hp at 6500 rpm

Power transmission
Multi-disc oil bath clutch, six-speed gearbox, chain drive.

landing gear
Double loop frame made of tubular steel, telescopic fork at the front, Ø 35 mm, two-arm swing arm, wire-spoke wheels with chrome-plated steel rims, tires 3.00-18 at the front, 3.25-18 at the rear, disc brake at the front, Ø 300 mm, drum brake at the rear, Ø 180 mm.

Weight with a full tank: 176 kg
Top speed: about 145 km / h
Construction time: 1974 to 1979
New price: 4,550 marks

Gerhard Eirich, editor, about the Hercules W 2000:
One thing is clear: anyone who drives a vacuum cleaner has to deal with the malicious comments. I find the W 2000 refreshing. The smoothness is great, the handling is like a 50s. Unfortunately, the cheap add-on parts also seem to come from this. No matter. Even with just 27 hp, swaying is fun. If only because of the certainty of moving a real motorcycle legend.

Norton Classic

wolf

From 1984 about 350 copies were already in service with the British police and provided plenty of experience.

engine
Air-cooled twin-disc rotary engine, compression ratio 8.6: 1, SU vacuum carburetor, Ø 38 mm.

Torque: 70 Nm at 7200 rpm
Chamber volume: 588 cc
Power: 85 hp at 9000 rpm

Power transmission
Multi-disc oil bath clutch, five-speed gearbox, fully encapsulated roller chain.

landing gear
Steel bridge frame open at the bottom, telescopic fork, Ø 38 mm, two-sided swing arm, six-spoke light alloy cast wheels, tires 100/90 V18 front, 110/80 V18 rear, double disc brake front, Ø 280 mm , disc brake rear, Ø 280 mm.

Weight with a full tank: approx. 235 kg
Top speed: about 210 km / h
Construction time: 1988
New price: approx. 18,000 marks

Stefan Gluck, test driver, about the Norton Classic:
“You want to drive a Wankel?” Asked colleague Eirich. You bet! Even the acoustics: the noise when starting the Norton
reminiscent of the start of a helicopter turbine, the sound of the BMW in-line six-cylinder. A pleasure! And this running culture! Driving is pleasingly unspectacular and still quite contemporary. Norton and me, we could be friends.

Suzuki RE5

wolf

Great technical effort should improve the smoothness and performance of the single-disc Wankels with 497 cm³.

engine
Liquid-cooled single-disc rotary engine, compression ratio 8.6: 1, Mikuni register carburetor, Ø 18/32 mm.

Torque: 74.5 Nm at 3500 rpm
Chamber volume: 497 cc
Power: 63 hp at 6500 rpm

Power transmission
Multi-disc oil bath clutch, five-speed gearbox, chain drive.

landing gear
Double loop frame made of tubular steel, telescopic fork, Ø 35 mm, two-arm swing arm, wire-spoke wheels with chrome-plated steel rims, tires 3.25-19 front, 4.00-18 rear, double disc brake front, Ø 295 mm, drum brake rear, Ø 190 mm.

Weight with a full tank: 260 kg
Top speed: 172 km / h
Time: 1974 to 1976
New price: 8700 marks

Burghard Schorstein, owner of the Suzuki RE5:
I’ve never looked for a rotary vehicle – it found me. We pulled ourselves together and a love-hate relationship developed that turns more and more into a great passion. For me, the RE5 has become a reliable, fascinating companion. It’s a shame that the concept wasn’t pursued any further, everyone drives 08/15 – I’m not going to give it back.

Van Veen OCR 1000

wolf

A rotary engine seemed ideal as a motorization: vibration-free, small, compact. And strong.

engine
Liquid-cooled two-disc rotary engine, compression 9: 1, Solex double falling flow carburetor, Ø 32 mm.

Torque: 135 Nm at 2500 rpm
Chamber volume: 996 cc
Power: 100 hp at 6500 rpm

Power transmission
Four-disc dry clutch, four-speed gearbox, cardan drive.

landing gear
Double loop frame made of tubular steel, telescopic fork, Ø 42 mm, two-arm swing arm, cast light alloy wheels, tires 110/90 V18 front, 130/80 V18 rear, double disc brake front, Ø 280 mm, disc brake rear, Ø 280 mm.

Weight full tank: 345 kg
Top speed: 191.5 km / h
Construction time: 1976 to 1978
New price: 28,200 marks

Anton Mayr, owner of the Van Veen OCR 1000:
Actually, I’m a Maico fan and collector. But with the Wankel virus came the desire for more. Now I have the Hercules, the Norton and the Van Veen. The 1000 is making good progress, and if you grab it right, you can move it pretty quickly. I’m good at it, and it will definitely increase in value. But why should I give it up??

The Wankel myth

Audi

Teacher. h.c. Felix Wankel at work: Constructing into old age.

Who was this man, how does the principle work and why did it not ultimately prevail? The Wankel myth explained in a condensed form.

Why should an explosion engine generate the power that is ultimately directed to a rotating crankshaft by means of pistons racing up and down and not immediately by means of pistons rotating around their own axis? This question occupied the eponymous inventor and inventor Felix Wankel, who later became Prof. h.c. appointed early on. Even as a schoolboy he devoured technology books, but ended his school career early in the 12th grade in order to complete an apprenticeship as a publishing clerk. The urge to tinker with and develop remained and culminated in the vision of an engine in which the pistons did not pound up and down, but instead turned. The advantages of the clocking engine should be combined with those of the combustion turbine. In 1926, when Wankel was just 24 years old, he had the first usable draft ready. He applied for patents, in 1934 a contract was concluded with BMW, another patent followed, but the project disappeared in a drawer.

After difficult post-war years, fate finally brought Wankel and NSU together. NSU needed him more because of his knowledge of rotary valve controls; conversely, Wankel didn’t have NSU at the top of his wish list either. He had tried to work with BMW, Daimler Benz, even MAN and General Motors, but received rejections everywhere. So the self-made designer, who was convinced of his idea, ended up at NSU and met Dr. Walter Froede – a fortunate circumstance, because without the head of the research department, who was a man with vision, the Wankel idea might never have made it to a functioning engine.

Advantages and disadvantages

The ingenuity of the principle is so obvious: in a cavity delimited by an epitrochoid, the triangular piston moves around its own longitudinal axis as well as around an eccentric. A full piston rotation is accompanied by three revolutions of the eccentric. The advantages of the Wankel principle are apparently obvious: A lot of power is produced from a small construction volume and only a few moving parts. The problems with the sealing strips have almost been eliminated over the years, and the high engine and exhaust gas temperatures have been tackled with appropriate oil cooling of the piston and liquid cooling of the entire engine. The advantages in terms of torque, smoothness and space requirements are still offset by the disadvantages in terms of consumption and emissions.

The motor, which was ultimately developed by NSU as a rotary piston engine (the trochoid no longer only rotates around its own axis, but also describes a circular movement due to the eccentric shaft stroke), and which was finally ready for series production, was not approved by Felix Wankel, who originally designed it Rotary piston engine (here the rotor and its housing rotate at a speed ratio of two to three in the same direction, each around their own axes that are offset from one another). Felix Wankel responded to the statement of the NSU chief designer about the very hot runner (“Do you really think that this red-hot dumpling will run?”) With clear words: “You turned the racehorse I had planned into a field horse. "

Wankel era didn’t last long

The NSU-Wankel ran, admittedly. It is still used today in the two-seater Wankel Spider, then in the Ro 80, and in the sports car of the Japanese licensee Mazda. The era of rotary motorcycles did not last that long, many designs did not even go into series production: Honda experimented from 1974 with a single-disk rotary motor with 124.7 cm³ chamber volume based on the CB 125, Kawasaki with the X99 project, a motorcycle with two-disk Wankel in a Z 900 chassis. Yamaha also presented a very presentable study at the Tokyo Motor Show in 1972, the RZ 201 with a liquid-cooled twin-disc rotary engine. But instead of the Wankel bike, models with in-line three-cylinders were further developed – the well-known XS 750 got the chance and went into series production.

Only Suzuki put its RE5 on sale. Norton finally stopped building in 1993 as the last two-wheeler proponent of the principle. Felix Wankel did not experience this anymore. He had already died on October 9, 1988. Perhaps, with a little more courage and patience, Wankel’s “race horse” could have been developed to the perfection it deserves.

Related articles

Related articles

Leave a Reply

Your email address will not be published. Required fields are marked *