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Ridefast Online Nov 2020

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The Rotary engine: Not

The Rotary engine: Not common at all in the bike industry. A rotary engine, like the ordinary reciprocating engine (where the piston goes up and down, both two and fourstrokes) gets its driving power from the same compression of fuel being compressed, burned and exhausted. However, where the normal engine must convert the power generated forcing the piston down the cylinder into a circular motion through the crankshaft, the rotary engine has a rotor spinning inside a chamber performing the same function. Engine configurations: Whenever you read a bike test – you’ll see that we often refer to what kind of engine powers the machine – ie – parallel twin, Vee twin, single cylinder and so-on. Some people confess that they often have no idea what we are talking about. There are plenty of non-technical people out there, so maybe, this will help. Please bear in mind that we are not boffins - we rely on our wives to tell us everything... But here’s what we do know… Here are some of the engine configurations on the market at the moment, or which have been produced in the recent past. Different configurations make power in different ways - IE: and inline four is generally smooth and is fairly predictable – while a V-Twin… well - ride one. You’ll get the gist of it. As the rotor spins in one direction only, and does not have to stop at the beginning and end of each cycle (four times per power cycle in a 4 stroke, and twice in a two stroke), it is continuously sucking in fuel, compressing and burning it as well as expelling the exhaust. The power shaft is being driven continuously. This makes for a very smooth and powerful engine. It produces more than double the power of either a two or four-stroke engine and has similar characteristics to a jet turbine engine. High power but woefully inefficient and very heavy on fuel, and it also produces an unacceptable amount of toxic emissions. Single Cylinder 2 Stroke It is also very complex and expensive to manufacture and maintain. Having said all of this it might still make a comeback as technology progresses because it has the advantage of small size, and it can run on almost any type of combustible fuel. Suzuki and DKW both bought licenses from Wankel in the mid 70’s, and whilst DKW brought out a lightweight rotary engine dirt bike, Suzuki produced the incredibly heavy and complex RE5. Nice bikes to ride, but thirsty and unwieldy, they were overshadowed by the excellent GS 750 and soon both the DKW and the RE5 faded away into history. Norton, in its first re-incarnation in the UK developed quite a successful 800cc rotary, which they again raced very successfully and ended up with a reasonably successful production rotary, which included a very reliable police version. Single Cylinder 4 Stroke Single cylinder: 1 piston that moves up and down. The piston and barrel can basically fave in any direction or be slightly inclined. Four stroke or two stroke. The vast majority of dirt bikes have these engines fitted, in various sizes. Most manufacturers offer a single of capacities from 50 cc up to around 700 cc. Water cooling, fuel-injection, electronics and balance shafts make them sophisticated and reliable. Popular Examples: Honda CRF450, Husqvarna Svartpilen, KTM690, Yamaha Grizzly 700. Parallel twins: Two pistons going up and down next to each other in a straight line. Four and two stroke. Once again most manufacturers have one or more parallel twins in their catalogue, ranging from 250 to 1200 cc, in both air-cooled and water cooled versions. Popular examples: Yamaha’s T7 and MT07 . BMW F850GS and XR900. Kawasaki Z650. Polaris RZR. Triumph Thruxton. Yamaha RD350. Triple parallel engines: Three pistons going up and down next to each other in a straight line. Four and two strokes. MV Agusta made the 3cylinder engine famous in their grand prix bikes, and the configuration is well-known for producing a very exotic exhaust note. While the Italian company was in one of the many limbo periods it has gone through over the years, Triumph brought out a 750 version which kept them going and helped to developed the current triple which has revived the company and made into a wonderful success. Yamaha, in typical Japanese style, have produced a brilliant triple cylinder bike the MT09, aimed at the market looking for something unique. We hope to see this engine in an adventure bike soon. Triumph also produced the monster Rocket - three cylinders fitted longitudinally in a huge cruiser frame which is surprisingly effective and popular. Popular examples: Triumph 800XC, Yamaha MT09. Significant is the fact that Suzuki and Kawasaki put themselves on the Superbike map with a selection of very nice two stroke triple-cylinder bikes. All of them were well known for great performance, reliability and smoothness. Only the move away from emissionemitting two strokes saw them being discontinued. In Line four cylinders: Four pistons going up and down next to each other. Every Japanese factory followed Honda’s lead with their original CB750 four that was based (copied) on the earlier Benelli 4 and 6 Cyl bikes. This is the engine that changed the world of Superbiking forever. Honda made history, but they only beat Kawasaki to the punch by a very short time, as the big K had their incredible (for the time) Z900 almost ready to launch. Had they brought it out first, the motorcycle industry may have looked a little different today. So popular is the in-line four that it has earned the tag of UJM….Universal Japanese Motor, and it is still one of the most popular big cylinder road bike engine to this day. It took BMW a while to make an inline four with their RR, but when they did, they were the first to give it just more than 200 BHP – unheard of back then. Inline fours are generallytoo wide to fit into adventure and dirt bikes, where you always look for a more compact design.. Inline Six cylinders: Six pistons going up and down next to each other. Big, wide, in your face… probably quite impractical due to the sheer size… In the early sixties Honda put themselves on the map with a wailing six cylinder four-stroke grand prix racer which dominated the 250 GP class at the time. Just the sound alone of this engine which peaked at 22000rpm in a field of thumping singles and some twin cylinder two strokes made everyone sit up and take notice of the Japanese manufacturer, and sent enthusiastic buyers into Honda showrooms worldwide. A classic case of how racing can sell product! When the other Japanese and the odd European brand brought out their competitors to the mighty Honda 750-4 and started to ease customers away from the big H they dropped another bombshell. The in-line 6 cylinder Honda CBX 1000 road bike. Honda proved their engineering skill and marketing savvy once again. Kawasaki soon followed suit with their Z1300… Due to the sheer size, weight and girth of these girls, neither bike handled very well… These days the only production inline six cylinder is the monstrous BMW touring bike, a machine big enough to need a reverse gear to get it out of a parking bay. Popular examples: Honda CBX1000. Kawasaki Z1300. Parrallel Twin Z650 Triple Cylinder Mv Agusta Inline 4 Cylinder Honda CBR1000 Inline 6 Cylinder BMW k1600 GT Single Cylinder Svartpilen 701