2010 Yamaha yz 250f
The 2010 Yamaha YZ250F dirt bike is another feather in the cap in the history of Yamaha dirt bikes. It has two side-oriented mounts surely a big upsurge in the area of frame design. As even the angles, thickness and shape of the aluminum is responsible for chassis balance and feel. Shock department faces a faces a huge change by the introduction of new KYB shock with a lowered spring. This motorcycle has improved the center of gravity and an ample room is availed for intake tract which is straight shot. A new set of damping settings for front fork which is unbelievably speed sensitive. The protector slider is now of steel instead of plastic and a new surface treatment for piston rod.
The Bilateral Beam frame is crafted from a carefully chosen combination of forged and extruded aluminum pieces – 20 in all – all welded together to provide unmatched rigidity balance.
The KYB® speed-sensitive front fork delivers exceptional damping feel, responsiveness, and bump absorption characteristics. Damping settings are revised, the piston rods have a new surface treatment, and the oil seal is a new design.
The 4-way-adjustable KYB® rear shock has been redesigned to make the most of the Bilateral Beam frame design. It’s lower in the frame for excellent mass centralization, and has new damping characteristics.
The new tank, seat, and rear fender are flat and the relationship between handlebars, pegs, and seat result in a natural, more forward riding position that facilitates rider movement. The fuel tank has been moved toward the center of the bike for mass centralization. The ProTaper® bars are four-way adjustable, and handlebar mounts and footpegs are 5mm higher to optimize rider position on the new chassis.
The handle bars for the all new 2010 Yamaha YZ250 dirt bike are 5mm taller with perfectly positioned foot-pegs. Pro taper bars are available with a one of its own kind Yamaha styling. The theme is light with fast directional changes. It also boosts a more spacious and forward seating enabling easier weight transfers on the sharp corners of an e-way. Good study has been done to improve the ride position
A new fuel tank is smaller and more compact. This fuel tank with a relocated petcock has a capacity ranging from 7 lit. To 6.4 lit. The designing is done in such a way that the fuel weight is centered and causes no trouble on the slashing turns carried out comfortably on the 2010 Yamaha YZ250F dirt bike. Also new brake pedal and changed kick starter shapes suit the frame. A one piece integrated water pump is simpler than the 2009 year two piece unit. The guard is made up of plastic this time.
The new body works for all new 2010 Yamaha YZ250F dirt are of plastic. It comes in two colors namely Blue/White and White/Red. The engineers have said to be envisioning an arrow while laying the mold. Its sharp horizontal styling movements and the overall looks are to ensure and indicate nibble handling and light weight characteristic of the motorcycle. The salient features of this bike in a nut shell would be neat seat shape, modified and newly crafted fuel tank its light weight character and a keen attention given to the riders comfort.
The 2010 YZ-250F Engine
Yamaha claims to have sold over 60,000 YZ250F motocross bikes since the model was first introduced in 2001. How’s that for an opening statement? Sixty thousand units, in motocross terms, is gigantic.
The five-valve Thumper redefined the small-bore class, made 125s obsolete overnight and its torquey, easy to ride nature made amateurs feel like Pros.For 2010 the YZ engineers have focused on optimizing the intake & exhaust systems, lightened the valve train, revised the carburetor settings and improved the ignition advance characteristics.
These improvements result in improved low to mid power and a more rider friendly engine with a more linear power delivery for improved drivability and control.New, liquid-cooled, 250cc, DOHC, 5-titanium valve, 4-stroke engine features a 13,500-rpm redline.Short skirt forged piston reduces weight and vibration, plus offers excellent durability.
The 13.5:1 compression ratio provides fast, controlled combustion and excellent engine performance.Optimized 5-valve (3-intake & 2-exhaust) combustion chamber design provides the most efficient intake and exhaust flow for maximum power.
Titanium valves decrease weight by more than 40% over a conventional steel valve train and reduce reciprocating mass for faster-revving.All new aluminium valve retainers reduce inertial mass for faster throttle responseNew “load reduced” valve springs reduce the amount of force required to open the valves and thereby minimizes power losses associated with friction and improves torque in the low and mid ranges.
Special chromium nitride coating on the tips of the intake valve stems reduces wear.Exhaust port shape has been revised from a round to a “D” shape to optimize flow and improve performance and engine characterRevised intake cam profile further improves performance.
The lightweight “liner less” aluminium cylinder features a ceramic composite coating which insures faster, more uniform heat dissipation, reduced friction and a longer service life.
Cylinder design features cutaways that allow the air trapped under the piston to enter a side chamber (or cutaway) to reduce horsepower robbing “pumping losses.”
The 2010 YZ-250F
Revised lightweight engine crankcase also utilizes special cutaways to reduce “pumping losses.” The crankcase cutaways match the cutaways in the cylinder for maximum efficiency.
Relocated convenient oil sight glass window and oil drain plug.
Lightweight magnesium cylinder head cover.
Dry sump lubrication system uses a remote oil tank reservoir positioned in front of the engine. This revised oil tank is lighter and more compact for 2010 and features a partition in the centre of the tank that improves the air-oil separation function. This tank is positioned low in the chassis which centralizes mass and lowers the centre of gravity for exceptional handling and a light feeling.
Oil volume in the engine has been optimized to reduce weight and “oil drag” related power losses.
Revised, 5-speed transmission features “involute splines” on the transmission axles to ensure smooth shifting and instant hook-up under power. The gear ratios for 3rd and 4th gears and the engagement dog shape have been changed to maximize the engine improvements. 3rd gear ratio = 26/18(1.444) while 4th gear ratio is 22/18(1.222).
Lightweight engine counterbalancer reduces vibration for improved rider comfort and less rider fatigue.
Revised multi-plate wet clutch features a revised clutch boss insert for improved wear, clutch spring load has been increased and the length of the push lever cam has been revised to change the lever ratio for an easier clutch lever pull and improved clutch feeling.
Lightweight, “quick-access” outer clutch cover provides fast, easy access for clutch maintenance.
Compact design automatic cam chain tensioner reduces maintenance and mechanical engine noise
Revised Keihin FCR-MX37 flat-slide carburetor with throttle position sensor (TPS). The carb settings have been revised to accentuate the improvements in the intake and exhaust systems. The cam for the accelerator pump has been optimized while the shape of the carburetor “throat” on the air box side has been modified for improved air flow.
The air box assembly has been revised for improved performance. The funnel shape at the air box “outlet” is optimized, while an all new straight design “boot” between the air box and the carb also improves air flow.
Washable, dual-stage, foam air filter.
Smokin YZ-250F
No fuss auto decompression system means fast, easy starting. The YZ250F restarts in any gear.
Convenient, handlebar-mounted hot start lever ensures fast starts when the engine is hot.
Revised CD ignition system delivers a precise spark and monitors engine rpm to insure optimal timing for fast, strong response at all rpms. The ignition timing advance curve has been revised for improved performance.
Direct ignition system means the ignition coil is integrated into spark plug cap to reduce weight and complexity.
New compact, lightweight, single core, dual radiators provide outstanding cooling efficiency. The location of the rads has been lowered and moved rearward for improved performance and protection while also lowering the all important center of gravity and centralizing mass. The thickness of the cores has also been increased. For 2010, the revised rads mount to the new frame at 3 points.
Lightweight titanium exhaust header pipe reduces weight, improves performance and allows hassle-free replacement of the oil filter.
The lightweight exhaust system utilizes a 4-stage expansion format that improves the cylinder filling induced by the exhaust pulse effect, resulting in excellent power characteristics.
Revised rigid mount muffler assembly is 50mm longer than last year for improved performance and reduced noise levels. The size of the internal diffuser pipe and the noise reducing “punched hole pipe” have been modified to achieve optimum performance.
The muffler can be repacked to maintain peak performance and reduced noise. The lightweight aluminium / stainless steel muffler complies with current CMRC & AMA noise regulations for 2010.
Trick, oversized “barrel adjuster” on the clutch lever perch allows on-the-fly clutch adjustments.