Fun, furious and frenetic - but not THAT FAST

Kawasaki's smaller three cylinder two strokes might have been every head-banging biker's dream but when it boiled down to it, the opposition was faster says John Nutting.
KAWASAKI’S two stroke triples of the Seventies stir up mixed memories for me.
Such as missing the boat to the Isle of Man for the TT because I spent almost as much time filling a KH400 at petrol stations as riding the bike from London to Liverpool. Or thinking I was a wheelie king during a photo session and crashing into the cameraman’s car.
But I was still thrilled by the image of the screaming three-cylinder two strokes. My first sight of one was during a holiday in Sweden in 1969. A young blade had bought a white 500cc Mach III and delighted in howling around the town of Uppsala where we were staying. The bike was beautiful; low and mean like a leopard waiting to pounce.
I had to wait more than five years to ride one of the triples by which time I was road testing bikes for the weekly newspaper Motor Cycle. Kawasakis at the time were being imported by Agrati Sales in Nottingham, which was closer to Midland Editor Bob Currie’s base in Birmingham. I briefly had a spin during 1972 on the fearsome 750cc Mach IV during a performance testing session at the Motor Industry Research Association’s (MIRA) proving ground at Nuneaton but it was Bob who did the mileage, taking a down-to-earth view of the machine.
For example, he recorded that the bike would take the 1-in-12 long drag of Hopton Bank in the Clee Hills in top gear. Likewise, he opted for a flat handlebar that cured high-speed handling woes.
Kawasaki’s triples were, however, the embodiment of naked performance, offering riders a passport to fantasies that light weight and low gearing can provide. They came from a time when petrol was cheap and abundant and worries about fuel consumption were almost non existent.
The 500cc Mach III and 750cc Mach IV were joined in the Kawasaki range by smaller S1 250cc and S2 350cc models, all sharing the same across-the-frame aircooled engines with triple carburettors and asymmetric exhaust systems, two pipes on the right and one on the left, quite unlike the balanced and mature look of the three-cylinder Suzukis, which were touring machines in comparison.
By the time I was able to get hold of a Kawasaki two stroke it was 1974 and the 400cc S3 had replaced the 350cc model. The Yom Kippur war had come and gone and fuel prices had rocketed.
Flexible bigger brother
LIKE its bigger brothers, the 350cc triple had a reputation for being highly strung and, no doubt in deference to the call for less frantic behaviour, the 400cc version was more flexible. Despite the capacity being increased by opening up the bore from 53 to 57mm and keeping the same stroke of 52.3mm, along with an increase in the carb size from 24mm to 26mm, the peak power dropped from 44 bhp at 8000 rpm to 42 bhp at 7000 rpm.
The chassis was largely unchanged: a duplex tube frame supported taut front forks and rear shocks in a 54.5 inch wheelbase. It had none of the refinement that Yamaha’s RD350 aircooled twin offered but had a combination of comfort and imprecision that maintained the raw image of the Kawasaki triple.
Mike Nicks, writing in Bike, caught the feeling well. “A change that has even greater repercussions for the rider involves the rear shocks,” he said in 1976. “These have been fitted with softer springs to add a velvet cushion touch to ride comfort. It works too — humming along a smooth main road on the KH is almost reminiscent of BMW’s superb ride control.
“But you’ve probably guessed the worst — Kawasaki haven’t got the equation just right and on rough roads the handling becomes less than reassuring. The underdamped rear end pitches and wags and some fairly intense concentration is required if you are going to keep it between the trees when travelling fast under such conditions.”
This was par for the course, though I’d not go so far to suggest that the ride quality was that good. But you could put up with it simply because the engine’s nasal drone from the three pipes — a product of its 120-degree crankpin layout — sounded so distinctive.
The 400’s power delivery was a lot less frenetic than the 350, making the bike easier to live with. This was a real bonus because its reputation was undiluted and many riders looked on the Kawasakis with a sense of awe.
Experience was the essence of the 400 Kawasaki because it failed to match the competition at the test strip. Suzuki’s later GT380 was faster outright, although the Kwak was quicker through the quarter mile.
Tested at MIRA in June 1974, the 400-S3 clocked a mean two-way top speed of 100.5 mph (just three mph down on Yamaha’s 350) and tripped the standing quarter mile in 14.75 seconds with a mean terminal speed of 88.8 mph. With good conditions, the time could be clipped to 14.4s.
What really stumped most testers was the rate at which fuel rushed through the engine. During our constant speed consumption tests at MIRA (conducted at corrected speeds on a triangular circuit that compensated for wind speeds) the 400 recorded one of the lowest figures ever, 24 mpg at 70 mph. This meant that you’d be topping up the tank every 70 miles or so, a real irritation over long distances.

The born-again DUKE

Red and raw compared to the more sophisticated 851 it may have been - but the revived SS was as pure a Ducati as its predecessor of the Seventies, says Roland Brown.
EVEN the spectators could see what was happening. I’d been roaring up to the same second-gear bend for the last hour or more, grabbing the brakes and then pitching the gleaming red-and-white Ducati into the corner for the benefit of the photographer’s camera before accelerating out, turning round and doing it all over again.
Back on that sun-scorched afternoon in central Italy in 1989, it hadn’t taken long for the noise to attract some interest from the locals. Before long a tiny Fiat had screeched to a halt, its occupants scrambling out to watch the show.
And when I’d paused for a rest, one young guy had stepped forward to give his verdict: “I can see the front move up and down - you need more damping, I think...”
He was right. I’d felt the new Ducati 900 Supersport’s front forks rocking a little over some tarmac ripples as I came out of the bend in one direction - I’d even stopped to make sure there was no damping adjustment available that might have cured it - but I’d never that imagined such minor misbehaviour would be visible from the side of the road, even to a guy who turned out to be a keen moto cross racer.
Compared to the thicker, adjustable forks of Ducati’s top-of-the-range 851 Superbike, which I had been riding earlier, the non-adjustable 40mm Marzocchis of the first ‘reborn’ 900 Supersport of almost 13 years ago were a bit soft and unsophisticated.
That was only to be expected, for the 900SS was intended not as a direct rival to the eight-valver but as a cheaper alternative for those who preferred their Bolognese dish red and raw.
The revival of those evocative initials was no coincidence, for this Duke was modelled along much the same lines as the thundering aircooled old 900SS model of the 1970s.
The new SS’s 904cc two-valve-per-cylinder motor, for a start, was cooled by a combination of air and oil, rather than by water like the 851 unit. Ducati had used the relatively cheap and simple air/oilcooling system on its Paris-Dakar Rally bikes in previous years.
Barely visible
TUCKED away behind the red-and-white fairing, the engine was barely visible. The 900’s steel trellis frame was red, too. It used the V-twin engine as a stressed member and held its rear shock unit at 45 degrees from a cantilevered swingarm.
Handlebars were low clip-ons that put plenty of weight on the pilot’s wrists at slow speeds; the seat was quite high, which gave the impression that you were sitting on the bike rather than in it.
There was a choke lever on the left-hand bar: pull it, then fire up and the motor spat into life with an unmistakable V-twin roar. There was plenty of mechanical noise, too, and the throaty exhaust bark - even through legally-restricted pipes - left you in no doubt about the bike’s character.
The hydraulic clutch was fairly light and the bike pulled away easily, but low-rev response was feeble. When the 900’s single Weber carb was opened up with the revs below 3000 rpm, the Ducati coughed and spluttered like a boy with his first cigar.
According to the firm’s engineering boss Massimo Bordi the answer was easily found, though. “There are caps welded into the rear part of the silencers; if you remove those the carburation will be much better. The torque is improved, too - but only for race use, of course!”
Once the motor had cleared its throat the 900 came alive at about 4000 rpm, smoothing out and pulling harder before really getting going at five grand. At 6000 rpm it was accelerating on past 100 mph, at seven it’s starting to vibrate a bit through handlebars and footpegs, and if you got to 8000 rpm in top you were well through 125 mph and not far short of the bike’s top speed, as well as approaching its 9000 rpm red line.
The 900 was not a particularly fast bike even by 1989 standards but at least it felt faster than it really was.

DON VESCO - 46 years of record breaking

When Don Vesco broke the world speed record last October for wheel-driven vehicles, it was just a continuation of his exploits with the fastest motorcycles on earth - and he did it on an ‘honorary’ motorcycle. John Nutting traces his incredible career.
WHEN Californian Don Vesco screamed across the Bonneville Salt Flats in the United States last October to claim the world speed record for wheel-driven vehicles, it wasn’t just the culmination of four years of attempts with the Turbinator, a bullet-shaped projectile built with his brother Rick.
At 62, Don Vesco has devoted a lifetime to going faster than anyone else in the world. Now he’s the been the fastest on both two and four wheels, having four times held the FIM world record, the last achieved at 318 mph in 1978.
For many, the wheel-driven world record for cars is the ‘real’ pinnacle of speed achievement. Pilot Andy Green’s supersonic land speed record in Richard Noble’s Thrust SSC 18 months ago at more than 750 mph was Herculean achievement but that vehicle was regarded by auto fans as a land-based jet aircraft.
Powering a wheel-driven vehicle at close to 500 mph through the wheels is as much - if not more - of a challenge. A measure of the challenge is that it’s taken 36 years to beat the late Donald Campbell’s world FIA record of 403 mph in Bluebird in 1964.
During each annual speed week held at the salt flats in Utah, Vesco inched closer and on October 17, with international timekeepers to record the event, he clocked 458 mph over the flying kilometre.
What’s great for bike fans is that, unlike Campbell’s Proteus-turbine powered Bluebird, the Turbinator used by Vesco is almost an honorary motorcycle. Though it has four wheels to comply with the requirements of the FIA (the governing body of the sport) each pair is no more than 17 inches apart. At first glance, the 31-foot long Turbinator looks similar to many of the motorcycle streamliners that Vesco has used over the years, though it is longer.
Powered by a Lycoming helicopter turbine developing 3750 ‘shaft’ horsepower at 16,000 rpm, it drives the wheels through a propeller shaft that runs down the left-hand side of the body, connecting to differentials between the 16 inch diameter wheels through wide toothed belts. Tyres are 24.5 inch diameter made by Mickey Thompson rated to 730 mph.
Like most turbines, the output shaft is not connected directly to the main shaft and works like a torque converter, with a varying degree of slip. So although the Turbinator has a 2:1 ‘gear ratio’ that would theoretically give 583 mph at the engine’s 16,000 rpm shaft speed, slippage reduces this. Vesco says he’s seen a maximum of 75 per cent slip, which roughly equates to his record speed of 458.44 mph.
Next year Vesco intends to beat 500 mph and then go on to regain the world motorcycle speed record that he lost in 1991 to Dave Campos, who recorded 322 mph in a streamliner powered by two Harley-Davidson engines.
Vesco knows that he can beat this because in 1978 he clocked a one-way speed of 333.117 mph on Lightning Bolt 1, a motorcycle streamliner powered by two turbocharged 1015cc Kawasaki engines.
Need for speed
BASED near San Diego, where he builds and tunes engines for midget car racing and motorcycles, Vesco’s lust for speed goes back to the Fifties. His first visit with a motorcycle to Bonneville Salt Flats was in 1955 at the age of 16.
His talent was noticed by the Honda factory and between 1961 and 1962 he was provided with a works RC161 four-cylinder 250cc race bike. A year later he provided Yamaha with its first US race victory with a win in the 250cc class at Daytona.
The same year, he joined the 200 mph club at Bonneville when he piloted his father John’s Offenhauser-powered four-wheel streamliner to a speed of 222 mph.
Recognising that a successful attempt on the world speed record required a machine looking more like a rocket than a motorcycle, Vesco followed the aerodynamic theme used by Johnny Allen to raise the US record to 214 mph with a Triumph engined streamliner in 1956 and Bob Leppan, who raised the record in 1966 to 245.6 mph with a double Triumph engined streamliner, Gyronaut-X1.
Vesco’s first two-wheel record breaking streamliner used two aircooled 350cc Yamaha TR2 racing engines. At Bonneville in September 1970 he became the first person on a motorcycle to break the 250 mph barrier with a two-way average speed of 251.92 mph, a new FIM world record.
It was a period of intense competition to be the fastest on two wheels. A month after Vesco took the record, American road racer Cal Rayborn, piloting a Harley-Davidson-powered machine, snatched it away with a new high of 265.49 mph.
Vesco returned to his workshop and rebuilt his machine with improved aerodynamics devised by Glyn Yakel. The engines were replaced with two 350cc TR2B racing Yamaha twins but there was still not enough power.
The two strokes made way for a pair of XS1 overhead camshaft Yamaha four stroke twins punched out to 750cc and using turbocharging, while the body of the streamliner was lengthened by 40 inches. Testing at Bonneville showed that the gearbox of one of the engines was too weak.