History of Yamaha YZF-R1
Rennie Scaysbrook
It was 1998. Yamaha released the first version of the YZF-R1. Newspaper publications around the world are being stolen and the company cannot keep up with the demand. The constant waiting list left hungry customers salivating, and Yamaha’s competitors were caught red-handed.
The 1998 Yamaha YZF-R1 is the ancestor of the modern supercar. Until its release (and for some time afterwards), the superbike was classified as a 750 cc four-cylinder and a 1000 cc twin. World Superbike will keep these rules until the end of 2002, but in reality, the world has moved on to 1998.
R1 saw that. The R1 also saw the death of the ’90s liter hyperbike (an overblown exaggeration term common at the time for any sports car larger than a superbike), which is said to have started when the Tadao Baba launched the mighty 1992 Honda Fireblade – a 900 cc inline four-cylinder – that made other four-cylinder rivals such as the Kawasaki ZZR1100 and Suzuki GSX-R1100 look like racing cars.
Sports cars at the time were primarily designed as road bikes, not race cars with lights. The R1 was the first to take this thinking and get rid of it. Comfort has been reduced to a bare minimum in the name of pure speed.
Even things like a handy under-seat trunk – just like the Fireblade had – were deemed unnecessary. Anything unnecessary is removed. The 998 cc R1 is designed to be the lightest, shortest and most powerful machine ever made in the 1000 cc segment.
It was designed to handle the agility of the company’s YZF600 ThunderCat (then the company’s flagship Supersport 600 machine), but has a power level typically reserved for factory WSBK racers Scott Russell and Noriyuki. Haga. R1 does not.
A clean sheet of paper
The mid-90s were a bleak period for superbike sales, and Yamaha realized that while the age-old YZF750 still performed well on the track, the sales success didn’t reflect that.
Thus, designer Kunihiko Miwa was given a blank sheet of paper to build a new super sports machine, right around the time the Yamaha YZF1000 ThunderAce was refreshed in 1997.
The ThunderAce has always been a reliable performer for the Tuning Fork brand, and the 1997 version is a really good machine.
It gets a lot of power from its inline 4-cylinder, 5-valve engine that can be traced back to the 1989 FZR1000, with a well-balanced chassis and good ergonomics, but it’s still in the Suzuki GSX weight class- R1100 and will be hard to do as a racer with light.
In that case, Miwa-san took the base engine of the YZF1000 and tore it to pieces. The R1’s engine retains the company’s sacred five-valve cylinder head, but that’s the similarity between it and the ThunderAce.
Miwa-san came to the conclusion that the traditional engine layout in which the crankshaft, drive shaft (opposite sprocket) and main shaft were all in a straight line was a serious waste of space, so he came up with a ‘three-axis’ design, where the main shaft is shifted and positioned above the crank and sprocket of the opposite shaft, closer to the crank.
This was soon adopted by the industry and is currently the only way if you want to build a serious inline four-cylinder superbike.
The new design also means that the clutch can now be mounted higher, with the cylinders and crankcase being cast in one unit.
This also allows Miwa-san to improve on traditional cast-iron cylinder liners, the holes of which are now treated with Yamaha’s patented electrodeposition low-friction ceramic coating.
Even the layout of the oil filter and cooler has been redesigned, placing them side by side in front of the block instead of stacked on top of each other as is commonly thought.
This gives Miwa-san the ability to fit the ends of the four-in-one exhaust system – which features a modified version of the EXUP (Exhaust Ultimate Powervalve) system – closer to the engine, giving him more room for front wheel and thus making the front even more compact.
The difference between the R1 engine and the ThunderAce’s isn’t just external dimensions. Inside, they may have shared a five-valve head, but the R1’s inlet ports are smaller, and inside the head there are smaller valves at a steeper angle.
The blocks are also different, with the R1’s diameter and stroke measuring 74 x 58 mm compared to the ThunderAce’s shorter stroke figures of 75.5 x 56 mm.
Below deck, the crankshaft was brought in to handle Jenny Craig. Yamaha’s engineers managed to reduce the impressive 22% mass of the crankshaft, which is the main factor creating the R1’s impressive throttle acceleration. Swinging out of the crank are new connecting rods with lightweight forged aluminum pistons.
Although the two engines share the announced torque figure of 107 Nm, the R1 – which carries a compression ratio of 11.8:1 compared to the ThunderAce’s 12.0:1 – makes that figure 1500rpm lower. min at 8500 rpm. It also has an additional 5 hp, with claims of 148 hp at 10,000 rpm.
Those are important numbers for 1998. Honda Fireblade, which in 1998 evolved into a 919 cc engine, claims power and torque of 130 hp at 10,500 rpm / 92 Nm at 8500 rpm. / minute.
Kawasaki’s ZX-9R, also modified for the 1998 model year, produces 143 hp at 11,000 rpm and 101 Nm of torque at 9,000 rpm.
These were still days before fuel injection became common on production sports cars, and rather than catch up with the EFI package, Yamaha opted to equip its new weapon with a carburetor. 40mm BDSR Mikuni, 30mm narrower than ThuderAce’s 38. unit mm
The R1 runs a throttle position sensor, which is also linked to a CDI unit, gear position indicator and EXUP valve, and is programmed to increase available torque from 4000-8000 rpm .
Catching all that squeal in the tires is a new six-speed transmission, replacing the five-speed transmission in the ThunderAce.
This new transmission became one of the few weak spots in the 1998 R1’s armor, but fortunately, Yamaha engineers were wise with this in 1999. Although this model was only expected there will be a paint color update – they’ve fitted a redesigned gearshift linkage and increased the shaft length shift gear to prevent it from bouncing off gears, especially the second gear.
The 1998 R1 is also subject to a worldwide recall, with a number of cases where the clutch-controlled gear drive disc broke, causing the engine to lock up.
But whatever the flaws, no matter how you look at the new engine, it was ahead of everything in 1998. The smaller, lighter, faster design brief was certainly met.
The new engine is 81 mm shorter from front to rear than the ThunderAce and 20.9 mm shorter from top to bottom. However, unlike the engine, the chassis did not have a platform for modification.
It had to be completely new – shorter and lighter, with a more distinctive shape than anything with headlights before. Yamaha claims the new bike weighs 177 kg dry, with more fuel in the tank it will be close to the 200 kg mark.
With the engine so small, Miwa-san can focus more on mass centralization than ever before. The engine is a fully loaded part of the chassis, which adds rigidity to the package…
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