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Technology: Weight comparison BMW F 650 GS – Suzuki GSX-R 1000

balance

Small fat and tall slender people often have only one thing in common among bipeds: their weight. The same applies to the very different two-wheelers Suzuki GSX-R 1000 and BMW F 650 GS. MOTORRAD acted as a weight watcher.

Sure, both have two wheels. But otherwise the concepts of the GSX-R 1000 and F 650 GS are as different as their target groups. The super sports car from Suzuki with its ultra-potent, 160 hp in-line four-cylinder for the race-infected sports driver, the single-cylinder enduro from BMW, which even beginners can easily cope with. Only the scales reveal an amazing commonality. The display shows 201 kilograms for both the Japanese and Bavarian women. But even if the bottom line is the same, it is clear that the sum is made up of very different individual parts. Where exactly the differences lie can only be shown by completely dismantling both motorcycles and weighing all components.
In terms of engines, the additional weight of Suzuki’s 59.7 kilogram four-cylinder power pack is surprisingly low at ten kilograms compared to the BMW single. Expressed in numbers, the muscle game of the GSX-R 1000 is: 370 grams of engine are required for each horsepower. With the BMW it is more than a kilogram. The crankshaft with its rotating parts such as the starter gear and alternator rotor weighs 11.3 kilograms, almost four pounds more than the oven-cylinder shaft of the Suzuki. Large counterweights for a reasonably proper balance of the first-order free inertia forces as well as a large centrifugal mass are necessary to wrest the single concentricity and proper vibration behavior.
Both have balancer shafts to minimize vibrations. But while this is supposed to compensate for the first-order inertia forces in the BMW, these are already fully compensated for in the in-line oven-cylinder by the pistons moving in opposite directions. Its balance shaft, which rotates at twice the crankshaft speed, weighs 720 grams only about half as much as that of the single cylinder? enough to balance the second-order inertial forces. The other weighty parts like the motor housing are closer together than expected. The complex, three-part engine housing with integrated cylinders of the Suzuki weighs 14.2 kilograms, the simple, two-part engine housing of the BMW with separate cylinder 11.4 kilograms, i.e. only 2.8 less.
The athlete also weighs more than the enduro when it comes to power transmission. Logically, the clutch and gearbox have to be significantly larger in order to transfer the considerable torque of the four-wheeler of 110 Newton meters than the 60 Newton meters of the single. Makes a difference of 3.1 kilograms.
When it comes to the periphery of the engine, the picture is very indifferent. Although the throttle valve housing of the Suzuki with its eight valves weighs 2.9 kilograms and thus more than three times that of the BMW counterpart with only one valve, the BMW makes its exhaust system difficult with 7.8 kilograms. Although only equipped with a stainless steel elbow, the two rear silencers made of the same material increase the weight.
The Suzuki system, which weighs only 6.3 kilograms, benefits from several things: On the one hand, lightweight materials such as titanium for the quadruple manifold and the collector with integrated roller as well as aluminum for the muffler press their mass, on the other hand they require the respective phase and thus Time-shifted combustion cycles of the four 250 cm³ individual cubic capacities result in a comparatively low damping volume compared to the massive explosions of the 650 cm³ single cylinder of the BMW. And finally, the GSX-R lacks a catalytic converter and lambda probe.
Despite this major disadvantage, the single-cylinder engine and its peripherals are a good ten kilograms lighter than the four-cylinder Suzuki, which has to catch up in other disciplines. The chassis, with its external appearance and material, the GSX-R is already claiming leadership. At just under eleven kilograms, the bridge frame, welded from sheet aluminum, is adapted to the strengths acting on it with different cross-sections, because it is 1.8 kilograms lighter than the bridge chassis of the BMW made of simple steel profiles with a constant cross-section. With the filigree rear frame made of rectangular aluminum tubes, the Suzuki downright outclasses the BMW. At two kilograms, the component weighs less than a quarter of the rear frame and the subframe at the rear and under the engine of the F 650. This means that the GSX-R is already earning more than half of the extra pounds in the engine section.
And it does one more thing in the chassis discipline. The seemingly massive upside-down fork of the Suzuki weighs 11.6 kilograms with handlebar stubs, fork bridges and steerer tube, 17.7 the conventional BMW component. Despite the two millimeters larger standpipe diameter, the athlete benefits from the lower spring travel of 130 to 170 millimeters. The additional weight of the BMW fork is also likely to be due to the more cost-effective construction of the simple component.
With the other chassis components, the Suzuki saves pound by pound, kilogram by kilogram. 0.9 for the swing arm, 1.2 for the suspension strut, although the user-friendly, hydraulic adjustment of the spring base on the F 650 takes additional toll. Likewise the tires of the enduro. The coarse 19- and 17-inch models with tubes at the front and rear have a weight of 1.3 kilograms each, despite their considerably smaller width. Even the filigree spoked wheels from BMW cannot compensate for this, which saves around three quarters of a kilo at the front and rear compared to the cast wheels from Suzuki. On the other hand, the individual disc brakes in the front wheel almost exactly outweighs the additional weight of the anti-lock braking system; both brake systems are equally heavy, except for a few grams.
So the balance after the chapters engine and chassis is: engine ten kilos ahead for the BMW, chassis 17.5 kilos for the Suzuki. As a result, the Bayern single has to score again with the attachments. The plastic fuel drum, which can hold one liter less in the BMW, is 2.6 kilograms lighter with the sensor and fuel pump than the sheet steel container in the Suzuki. This also has a full cladding that weighs almost four kilograms more than the partial cladding of the BMW. The cooler, which has to provide a corresponding cooling capacity for the multiple performance potential, weighs more than two additional kilograms together with the oil cooler, which the BMW does not need. On the other hand, the Enduro has add-on parts such as the engine protection for rough terrain or a main stand, which in turn cause 3.5 kilograms of extra weight. The GSX-R 1000 is still 4.8 kilograms missing, which ultimately creates the balance between the two when it comes to operating materials due to the larger coolant content, the slightly larger tank volume and more engine oil.
D.The same overall result of 201 kilograms is made up of components with completely different weights. The entire GSX-R series has been subject to strict weight dictates since its inception and can therefore shine in terms of design and materials. Any further diet would result in high costs. Unlike the BMW, which could easily lose 20 kilograms with the same means without being a less robust travel enduro. Your functionality would even increase, the driving pleasure? the ascetic neighbors from the Alpine region prove that ?? would even go up. But maybe the people of Munich will leave wheat beer and pretzels out of their GS and prescribe their sushi as a light food.

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