HEART OF THE MATTER
Suzuki’s 16-year power play with the GSX-R1000
Go big or go home
When it comes to design, there isnõt anything particularly special about the original GSX-R1000 engine. It is essentially a larger- capacity GSX-R750 Y motor. So why did it cause such a stir? Itõs all down to capacity, efficiency and reducing mechanical friction losses.
With the K1ÕS DOHC inline four, Suzuki concentrated on getting the air and fuel into the cylinder as fast as possible and at the optimum ratio before burning it at the right time and harnessing as much of the power produced as possible with minimal losses. This was achieved by using a fast 16-bit processor in the bikeõs ECU that was matched to an eight-point crank sensor (double the number of sensors on the GSX-R750 and twice the processing power) and Suzukiõs dual throttle valve system.
To ensure mechanical friction was kept as low as possible, the balancer shaft runs in plain insert bearings rather than roller bearings and weight was trimmed off moving items such as pistons (which are 3g lighter than the 750Õs), valves, cams, etc. The net result was considerably more power and torque than its rivals, as well as a lighter overall kerb weight, and therefore a faster sportsbike. Simple engineering principles done well Ð how very Suzuki.
Strengths Sheer power and torque combined with a light overall weight. Weaknesses The chassis couldnõt always deal with the power. Impact The K1 set a new performance target for litre bikes. Any updates? The K3/4 engine gained a 32-bit processor, new injectors and new ventilation holes to equalise internal engine pressures. Power was increased by 3bhp.
‘It’s all down to capacity, efficiency and reducing friction losses’
All about the balance
With the Motogp project decided as a V4, the new GSX-R1000 engine was developed purely for the road and as such gained a 0.4mm bigger bore to take it to 998.6cc. Inside the cylinders, new pistons were lighter and the compression ratio was raised from 12:1 to 12.5:1 and matched to 1mm larger intake valves that were made of titanium for the first time, saving 94.4g.
Seeking to gain more of the benefits from equalising the engine’s internal pressure, the ventilation holes between cylinders were increased in size by 4mm and the crank and con rods strengthened to deal with a claimed 17bhp increase in power and a new 1000rpm higher, 13,500rpm red line. A new twin injector fuel-injection system with the secondary one only operating at high rpm was also new.
Alterations to the gearbox, which had become notorious for its weakness, saw the shift fork redesigned, the ratios moved slightly closer together and a slipper clutch fitted for the first time. However, what really made the K5 stand out was the unique titanium trapezoidal exhaust.
Strengths Despite its increase in power, the K5’s new chassis and overall balance allows riders to harness this extra grunt.
Weaknesses Very few, it’s still a wonderfully complete package.
Impact The K5 demonstrated that raw power isn’t anything without control.
Any updates? The K7/8’s handling was ruined by heavy twin exhaust pipes and more relaxed chassis geometry, however the engine gained 4bhp through larger ventilation holes, new injectors and it also debuted a world first of variable power modes.
With the unpopular K7/8 model seeing the GSX-R1000 knocked off its perch at the top of the superbike tree, Suzuki’s problems were compounded by the arrival in 2008 of the new Honda Fireblade. But they had a plan.
The K9 was powered by a new GSX-R motor that while not radically different in its overall concept, did have some substantial changes within it. To increase the swingarm’s length for better drive, the K9’s engine was made 59mm shorter front to back than the old K5 engine, allowing Suzuki to fit a 32mm longer swingarm. This shortening was achieved through a new stacked gearbox (like the GSX-R600 and GSX-R750’S design) and reducing the engine castings from three to two.
Inside the motor the bore was increased by 1.1mm and the stroke reduced by 1.7mm, in keeping with the ‘over-square’ philosophy of modern sportsbikes, and the pistons re- profiled to go with an altered head and cams. Inside the head the GSX-R’S inlet and exhaust valves grew 1mm to 31mm and 25mm respectively while double valve springs were also added. Finally, to boost the motor’s midrange, the length of the intake trumpets was varied with the two inner ones longer than the outer two.
When you look at the spec sheet, Suzuki went to town with the K9, however their rivals went even further and the new crossplane Yamaha R1 and BMW S1000RR rather took the shine off Suzuki’s latest GSX-R.
Strengths The engine’s midrange. Weaknesses The S1000RR was more powerful and had electronic rider aids. Impact The K9 failed to set the world on fire and, sadly, was largely forgotten about.
Any updates? The GSX-R1000 L2 was the last GSX-R1000 model before the radically different 2017 bike. It uses the same basic motor as the K9, however Suzuki made some significant alterations within it to boost its power and torque. The pistons are 11% lighter and the compression ratio is increased thanks to a reshaped piston crown. A lighter valve train is operated by re-profiled cams with an altered duration on the exhaust port but the same as the K9 on the intake to reduce the valve overlap and boost top end. Under the pistons, the ventilation holes are redesigned to reduce pumping losses and the fuel maps tweaked. Suzuki only claimed a power increase of 1bhp, but the bike felt healthier and also lighter handling thanks to a new single exhaust and altered chassis.
‘Suzuki went to town with the K9, however their rivals went even further ’
The K1 engine exposed in all its component glory With 161bhp, the K1 moved the power game on another leap Nothing overly clever, just an optimisation of the burn Redline of 12,500rpm meant big midrange The K1 still looks classically GSX-R mean
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GSX-R1000 K5 to K8 2005-2008
Producing 164bhp requires lots of air BPF forks arrived with the K9 model A wide back is a typical GSX-R look The K9 was far from a dog, yet proved unpopular
GSX-R1000 K9 to L6 2009-2016 When it comes to grunt, the L2 engine has it in spades and is vastly under-rated