2010 | Page 73 of 86 | BikeAdvice - Latest Bike News, Motorcycle Reviews, Electric Vehicle Updates

For all non knowers, let us, at the very onset, inform that Yamaha YZ450F is a racing motocross motorcycle developed as a replacement for the YZ250. When Yamaha launched this bike in 1998 it was the first production motorcycle which directly competed against two strokers. In 2003, YZF received the biggest revamp with an increased displacement to 450cc (from the initial 400cc) with a peak power output of 52 horses. Then again in 2006, this bike went for a major overhaul and returned with over 300 changes. And then came 2009 wherein Yamaha broke all barriers and came up with a devastatingly different and shatteringly innovative design. The 2010 YZ450F launched in 2009, had a rearward slanting engine!!! No we did not misprint it! The engine is tilted 9 degrees behind its vertical axis. The YZF revolutionary rearward slanting cylinder positions its mass closer to the center of the machine than ever before. How was this achieved? Every year Motocross bikes goes through the very known improvements, frames get tweaked, materials added here and there, parts removed/ added, swingarms increased or decreased in length and rigidity, suspensions reworked etc. Yamaha wanted to achieve all this with some difference. Yamaha sat on a different stream and came out with a incredibly different concept for achieving the right kind of a balance by rearranging the engine and its components (obviously along with the above mentioned tweaks). The realization was that the singlemost heaviest component of the motorcycle, the engine needs some alteration. The tilt is such that it is moved rearwards by as much as 13 degrees as compared to the previous version. The biggest hurdle Yamaha faced was that by tilting the engine rearwards, there was no place left for the carburetor. Yamaha replaced the carb with a Fuel Injector unit which instantly adapts to the varying air-fuel mixtures depending on different heights and temperatures. The battery less Fuel Injector is powered by a 14 volt /110 watt high output generator. With the induction system located at the front of the bike, fresh air is pulled into the engine through twin air intakes above both the radiator shrouds (Yes, two radiators!). It helps in delivering a cleaner, less dusty air inside. A 44mm Keihin throttle body receives fuel from a 12 hole fuel injector and is designed for easy starting with an integrated cold starting. With the airbox moving to the front part of the bike, the underseat area became vacant which allowed Yamaha engineers to fit the rear shock absorber at the center of the chassis where it provided the right kind of performance and balance. Furthermore, both the radiators were lowered and tilted forward. Moving to the engine bit, the cylinder is also angled towards the front center of the crankshaft to keep the connecting rod more vertical during the compression stroke. This reduces friction between the piston and the cylinder walls translating into less wear and tear and better performance which goes along with quicker and a fantastic throttle response. The engine is also shorter by more than half an inch courtesy a bigger bore of 97mm and shorter stroke of 60.8mm. Another change in this edition is the introduction of the conventional four valve titanium design from Yamahas five valve cylinder in the previous iterations. In the overall redesigning process the bike gained five pounds over the earlier iteration and now stands at 245lbs at the weighing machine with a full tank of fuel. The exhaust has also been radicalized and is now tornado swirling pipe under the seat which allowed engineers to enhance the low and mid range of the engine. The engine specs read something like this: a radical rearward slanting 450cc 4 valve DOHC engine which produces maximum power of 55.5PS at 9000 rpm and a peak torque of 4.8 kg-m which comes at 7000 rpm. The rearward slant enables unmatched centralization of the mass which is now concentrated towards the center of the machine. The bike comprises of an advanced Bilateral Beam all aluminum frame with components assembled for a near perfect mass centralization. The new frame provides exceptional performance and superb rigidity which complements the engine which in turn helps during acute cornering and ensures razor sharp handling. The frame has been designed with absolute precision from a carefully chosen combination of forged aluminum for extra light weight and fantastic rigidity. The front and rear fenders, along with the number plate, side cover and front fork protector are redesigned for a fiery look and the use of plastic has been minimized to expose the lovely looking and functionally fantastic lightweight aluminum frame. Having read so much about this engineering marvel from Yamaha must have given you a slight hint of the heavenly price this bike would/ could have made it to the sales counter. Let us shatter your estimates, this bike comes at a lip smacking MSRP of $7990 for the Team Yamaha Blue/White model and did we say only! Another variant in White/Red would set you ‘rear’ by $8090. These prices prove that innovation doesn’t need mandatory sky rocket price tags. For this amount you get a machine that delivers exceptional performance and precise handling anywhere and wherever you want! - Saad Khan Technical Specs: ENGINE: Type : Liquid cooled 4-stroke, DOHC, 4-valve, rearward slantingsingle cylinder Displacement : 449.7cc Bore and stroke: 97.0 x 60.8mm Compression ratio: 12.5 : 1 Max. Power : 40.8 kW (55.5 PS) @ 9,000 rpm Max. Torque : 47.1 Nm (4.8 kg-m) @ 7,000 rpm Lubrication : Dry sump Carburettor : Fuel Injection Clutch type : Wet multiple-disc Ignition : Full Transistor Starter system : Kick Transmission : Constant mesh, 5-speed Final transmission: Gear CHASSIS CHASSIS Frame : Bilateral Beam frame Front suspension: Telescopic fork Front wheel travel: 310 mm Rear suspension: Swingarm (link suspension) Rear wheel travel: 312 mm Front brake : Hydraulic single disc brake, Ø 250 mm Rear brake : Hydraulic single disc brake, Ø 245 mm Front tyre : 80/100-21 51M Rear tyre : 110/90-19 62M DIMENSIONS: Overall length : 2,191 mm Overall width : 825 mm Overall height : 1,311 mm Saddle height : 999 mm Wheelbase : 1,487 mm Min. ground clearance: 383 mm Wet weight (including full oil and fuel tank): 111.9 kg Fuel tank capacity: 6.0 litres Oil tank capacity: 1.2 litres Inquisitive and baffled?... Read more here.

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