Dirt Bikes
Yamaha - Motocross
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YAMAHA YZ85/YZ85LWE Sand, rocks, soil, loam, playing in the dirt comes naturally to kids. It’s just that while some kids are happy to build roads through it with their toy dump trucks, others crave an earthmoving style that’s a little more… efficient. Liquid-cooled, 85cc crankcase reed-valve inducted six-speed delivers hardhitting, moto-winning power throughout the RPM range. Smooth-shifting, six-speed close ratio transmission with heavy-duty, multiplate clutch delivers maximum hook-up for outstanding acceleration and cornerexiting power. Rear suspension features fully adjustable Kayaba link-type shock with race-tested compression damping valving. Lightweight 36mm inverted Kayaba cartridge fork features compression and rebound damping adjustability, with lowfriction outer tubes and internals. Involute spline clutch design means smoother shifting under power with great durability at competition-level usage. Tough, semi-double cradle frame is lightweight and strong for sharp handling for riders from rank Novice to Mini Expert. |
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YAMAHA YZ125 Ask around the pits and you’ll be surprised how many riders of bigger, faster motorcycles hold a very special affinity for Yamaha’s YZ125 – it’s a legend in motocross. Winner of a swag of championships and magazine shootouts, the YZ125 also benefits from new race rules allowing up to 144cc capacity – perfect for taking on the 250Fs. Amazingly compact 124cc reed-valve inducted two-stroke helps produce an awesome power-to-weight ratio. Six-speed, close-ratio transmission optimises gear ratios for maximum performance. 38mm Mikuni TMX carburettor gives excellent throttle response and serious horsepower. Patented YPVS power-valve system combines crisp, hard-hitting bottom-end acceleration with strong midrange and eye-opening top end. YZ250F-style front-brake caliper and wave type front and rear discs minimize unsprung weight and provide excellent stopping power. A carefully engineered, advanced aluminium frame and swingarm give the YZ125 the best handling in the class. Removable aluminium rear subframe constructed of square-section tubing for reduced weight rebound system for increased comfort all add up to fantastic rear wheel control and a sweet ride. Repackable exhaust silencer. |
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YAMAHA YZ250 What do an army of freestylers, motocross riders, hard-core weekend trailriders and elite level cross-country racers have in common? A passion for the punchy two-stroke power and agility, latest chassis technology and easy-on-the-wallet upkeep of Yamaha’s YZ250. 249cc liquid-cooled reed-valve-inducted two-stroke engine is lightweight, compact and features an incredibly wide, hard hitting powerband. Smooth-shifting, five-speed, close-ratio transmission with heavy-duty, multiplate clutch. YZ250F-style front-brake caliper and wave type front and rear discs minimise unsprung weight and provide excellent stopping power. 48mm forks feature the Speed-Sensitive System that uses piston speed to control damping force for super-precise handling and a smooth ride. 38mm Keihin PWK carburettor with power jet and throttle position sensor (TPS) ensures precise fuel/air mixing and extra-crisp throttle response throughout the powerband. Patented YPVS power-valve system combines crisp, hard-hitting, bottom-end acceleration with strong midrange and eye-opening top-end. Large-capacity radiator features a ten row core with four louvres for maximum cooling efficiency. Digital CDI ignition system delivers precise spark for faster, stronger response anywhere in the powerband. |
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YAMAHA YZ250F Ask any motocross rider where races are won and lost and odds on he’ll tell you its all in the corners. A light, nimble and supreme handling MX bike can pick its lines and stick to them, enabling its rider to hang on longer and go harder. Yamaha’s YZ250F retains its carburettor design which is one of the main reasons for this model retaining its status as the lightest bike in the 250cc class. However, the carb size has been beefed up to 39mm and the optimised engine pumps out more power in the 8000 to 12000 rpm range. This increased hit combines with outstanding throttle response thanks to new crankshaft webs, a new vibration reducing counterbalancer, new connecting rod, and low friction piston rings as well as a new piston, piston pin, and clip assembly. The new Bilateral Beam frame has revised rigidity balance for superior cornering performance as well as great stability on rough, highspeed straights. Beefy new front KYB suspension components plus revised rear shock internals and more rigidity in the swingarm axle block area give this new machine a serious handling advantage with light, quick steering and zero headshake. Engine refinements, including a larger 39mm carburettor, optimised CDI, and lighter piston with a lighter piston pin, mean YZ250F has more power as well as exceptional throttle response in the midtohigh speed range. The crankshaft web design is revised to match the lighter piston and reduce highrpm vibration. The air cleaner cage is a new design that provides increased airflow, contributing to the excellent throttle response in the midtohigh speed range. The new Bilateral Beam frame with a revised balance of longitudinal, lateral, and torsional rigidity is used for superior cornering performance, especially while exiting turns, as well as great stability on rough, highspeed straights. YZ250F has beefy new outer fork tubes and triple clamps. The result? An increase in the front fork assembly’s torsional rigidity for unmatched chassis stability. Fork offset has been changed from 25mm to 22mm to accommodate the new frame design. This shortened offset increases trail length which, in turn, contributes to excellent stability and reduces the inertial moment of the front fork assembly for quick, racewinning handling. The rider can take advantage of the higher level of performance throughout the turn. |
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YAMAHA YZ450F When an existing design approaches its limits, it’s time to call in the revolutionary thinkers. The creative minds who aren’t afraid to throw everything out and start from scratch. Which is exactly what happened with the latest incarnation of our championship dominating MX bike. Accepted wisdom has been turned on its head to produce our most effective motocross bike yet. Meet the revolutionary new YZ450F. The solution looks simple, but the decision was bold… take mass centralisation in a new direction by fitting a rearward facing and backward tilted cylinder. Now the heaviest part of the bike is closer to the middle… right where it needs to be for amazing levels of flickability. But theory is nothing without practice to back it up, so Yamaha testers nailed berms, scrubbed jumps and blitzed straights lap after lap to fine tune the new design, to confirm the agility of the new bilateral beam frame, the linear power delivery offered by the sweet fuel injection system and awesome punch from the high torque four-valve motor. It’s not change for change’s sake. It’s the lightest handling, whoop-skimming YZ450F yet. YZ450F’s new rearward-slanted cylinder is a revolutionary advancement that achieves unmatched mass centralisation, concentrating inertial mass toward the centre of the machine. This bold new design also swaps traditional intake and exhaust positions, putting the lightweight airbox and throttle body out front. This contributes to mass centralisation for nimble handling while also achieving a straight intake tract for superb combustion efficiency that delivers more power. The cylinder is offset so the connecting rod is vertical at the moment of greatest combustion force, minimising piston friction against the cylinder wall that could rob power. That means quicker response. The new 4-titanium valve cylinder head is matched to a fuel injection system developed specifically for the YZ450F. Instantly adapts to changing air/fuel mixtures depending on altitude and temperature, for an engine that delivers no matter what conditions. The all-new aluminium Bilateral Beam frame provides a superb rigidity balance that complements the engine for unmatched lightweight handling and cornering. The result? The best cornering, most nimble 450F for all track conditions. Revamped looks deliver new-generation styling, including front and rear fenders, intake cover, front fork protector, and number plate, along with the fuel tank and seat. Accessory GYTR Power Tuner lets bike tuners adjust air/fuel mixture and ignition timing maps to match engine performance characteristics to the rider and track conditions. The rearward-slanted engine allowed engineers to design straight intake and exhaust ports, creating the most direct path for air flow into the fuel-injected engine for incredible performance. The YZ450F uses a battery-less fuel injection system with a 12-hole injector for superb fuel atomization. The 44mm Keihin throttle body is designed for easy starting, with an integrated cold start and idle speed adjustment knob. Yamaha FI provides optimal air/fuel mixtures in all altitudes and wide range of temperatures for outstanding throttle response. 14 volt / 110W high output generator powers the battery less fuel injection system. 4-titanium valve cylinder head with a “pent-roof” design combustion chamber provides excellent combustion efficiency and unequalled power output. Intake and exhaust camshaft profile changes to increase valve working angle and valve lift for most excellent performance at all rpm. Bigger 97.0mm bore and shorter 60.8mm stroke, along with a higher 12.5:1 compression ratio, create a combustion chamber that delivers really impressive power. Air filter case is changed to accommodate new engine layout. Putting it up front keeps dirt and dust kicked up from the rear tyre away from the intake system. New “tornado-style” exhaust header with resonator efficiently scavenges exhaust gasses and helps the engine achieve its exceptional low-to-mid range torque characteristics, while the 150mm-longer muffler comfortably meets the latest noise standards without a sacrifice of power. Clutch and transmission components have been thoughtfully revamped to give the rider great shifting feel. Aluminium Bilateral Beam frame is crafted from a carefully chosen combination of forged and extruded aluminium, 16 components in all, for the right rigidity balance and light weight. New skid plate is constructed from tough polypropylene for great protection and low weight. Swingarm and rear shock are redesigned, with the shock mounted along the central axis of the frame, taking advantage of the space no longer needed for the front-mounted airbox. This optimised combination delivers exceptionally linear performance for excellent bump absorption and awesome cornering ability. KYB Speed Sensitive front fork has 10mm longer stroke for excellent feel and shock absorption. KYB rear shock with large capacity piggy back reservoir and 50mm piston for more consistent damping control. New fuel tank is positioned underneath the seat, contributing to the centralised mass. The seat is long and flat for to allow free rider movement. New rear sprocket shape has a trick appearance and is light weight. Triple clamps are redesigned, with a change in offset from 25 to 22 mm for unequalled cornering performance. ProTaper bars are four-way adjustable to accommodate a wide range of riders. Front and rear fenders, along with the number plate, side cover and front fork protector have been redesigned for an aggressive look. Less plastic is used to expose and enhance the lightweight aluminium frame. Fuel pump is small and lightweight, as is the compact transistor ignition unit. |
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