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– 2006 Yamaha YZ450F
Powerful as ever, yet easier to ride. Lighter feeling and better balanced.
Those were the engineering goals for the all new YZ450F. So the engineers went to work and developed a new lighter aluminum frame, a new engine and a new 5-speed transmission. But the story doesn’t end there. The new engine has been closer to the centre of the bike for a lighter riding feel. When winning counts, count on the new YZ450F.
All new, liquid-cooled, 449cc, DOHC, 5-valve, 4-stroke, single with titanium valves delivers a broad power curve with a great over-rev capacity.
Automatic decompression system ensures easy starts in any gear with no manual lever to fuss with.
New compact cylinder head design utilizes lightweight titanium valves and load-reduced springs reduce reciprocating mass for less friction, faster-revving and smoother-hitting power delivery across the rev range.
The decompressor boss has been removed and the head features a taller deck and new boss design for increased stiffness. The exterior head to cylinder mounting bolts are now accessible from the top side for improved serviceability.
New intake port shape increases the velocity of the incoming charge for more complete cylinder filling and more power.
New design cam caps for improved durability and reliability.
Cylinder inclination angle has been reduced to centralize mass and bring the center of gravity closer to the rider for improved weight distribution and lighter handling.
The cylinder features a ceramic composite coating which insures uniform heat dissipation, reduced friction and a longer service life.
All new lightweight crankshaft decreases inertial mass for fast throttle response.
New connecting rod design is used for improved durability
New short-skirt, forged piston provides excellent reliability and reduces weight too.
New piston oil cooler utilizes a pinpoint nozzle that directs oil to the desired portion of the cylinder and piston, to reduce piston, cylinder and rod temperatures for improved durability.
Oil volume in engine has been optimized to reduce weight and oil drag related power losses.
All new balancer shaft reduces vibration for improved rider comfort and less rider fatigue.
All new crankcase design features an integrated oil tank inside the cases to supply oil to the dry sump lubrication system. This new design concentrates mass lower in the frame for optimum handling and lighter weight feeling.
The new crankcase features a tri-axis design layout for the crank, main and drive axles. This tri-axis design keeps the crankcases more compact while also centralizing mass for better handling. All of the shafts are positioned low in the cases to maintain a low centre of gravity.
The external dry sump oil lines have been removed since the oil is no longer carried in the frame. The benefit is both reduced weight, cleaner appearance and improved serviceability.
New 5-speed transmission optimizes the engine performance. Primary reduction ratio is 61/23 (same as ’05) while the secondary ratio is 49/13 (’05 is 51/14). The new crankcases are slightly wider than in ‘ 05 to accommodate the new 5-speed transmission. This new 5-speed transmission allows for improved performance and the possibilities of a wider range of uses.
New design kick start lever, ratchet and internal mechanism helps to facilitate easy starting and improve kick starter durability.
Convenient, handlebar-mounted hot start lever means easy starting when the engine is hot.
Keihin FCR-MX39 flat-slide carburetor with throttle position sensor (TPS) and leak jet type accelerator pump delivers ultra-precise fuel/air mixing and instant throttle response. The carb setting and jetting has been revised to match the engine improvements and to provide instant throttle performance.
New design air box to carb boot maximizes airflow into the engine while the washable, dual-stage, foam air filter reduces maintenance costs and provides excellent filtering qualities.
CD ignition system delivers ultra-precise spark and timing for faster, stronger engine response during hard acceleration, and less kickback during starting.
Ignition coil is integrated into the spark plug cap to reduce weight and complexity.
Quick-access, lightweight magnesium outer clutch cover for fast, easy clutch maintenance.
Revised, compact new single core dual radiators provide outstanding cooling efficiency while the reducing weight due to optimized capacity. The rads are less tall and thinner for 2006, yet provide improved cooling Vs the 2005 rads. The directional fins inside the rad shrouds have been revised for improved air flow through the rads.
Trick, works-style clutch lever features a race-spec “barrel adjuster” for on-the-fly adjustability. There is a new, larger boot covering the adjuster that provides more grip for easier operation.
Lightweight titanium header pipe with titanium heat shields. Special header pipe angle maximizes engine power and allows hassle-free access to the oil filter.
Lightweight aluminum / stainless steel muffler reduces weight while its re-packable design maintains optimal engine performance and reduced noise levels.
All new compact aluminum semi-double-cradle frame features a cast steering head while the remainder of the frame uses forged, pipe stock and extruded components. Yamaha has maintained the semi double cradle design to allow for “controlled flex” to optimize suspension action. The new frame provides a lower centre of gravity for a light feel and razor sharp handling, plus less rider fatigue, and excellent stability. Over the years, the “knock” on aluminum frames is that they were too stiff and therefore make suspension set-up difficult and may provide a harsh ride. Yamaha has changed that with the semi-cradle design.
Removable rear sub frame is constructed of square-section, lightweight aluminum pipe. Detachable design allows easy access when servicing rear suspension components.
New, lightweight, tapered, aluminum swingarm is produced using “hydro forming”, a special forming method that uses high pressure water to form shapes. The new swingarm provides improved overall chassis balance thanks to the addition of re-enforcing ribs in the cast aluminum around the pivot area. The result is a 2% increase in torsional rigidity for improved handling.
New, cast aluminum upper triple clamp provides an increase in rigidity (longitudinal torsion) for improved handling.
New forged lower triple clamp features an increase in longitudinal rigidity which allows greater flexibility to absorb the forces applied between the front fork and the frame for improved handling.
All new Pro Taper handle bars reduce weight and improve durability.
New adjustable handlebar mounts allow the handlebars to be moved 10mm rearward if desired.
New, lighter, improved 48mm, adjustable, inverted, Kayaba cartridge forks feature a revised twin-chamber design. The twin chamber design means the damper unit is in a separate structure which prevents aerated fork oil from entering the inner damper assembly and degrading its damping abilities. Since the inner damper is pressurized, it also eliminates bubbles forming in the oil.
For 2006, the balance between the inner and outer tubes has been optimized, while the Kashima coating on the pressure tank and the piston rod reduce friction for smoother suspension performance. The cylinder diameter has been revised from 25 to 24mm for improved primary cushioning and a low friction oil seal has been used. The weight of the fork assembly has been reduced by 2.5%
The 48mm KYB fork also features a relocated Transfer Control Valve (TCV). The TCV enhances the damping force of the inner damper from mid stroke to full stroke and improves bottoming characteristics. The benefit of TCV is more precise control throughout the full stroke range. For 2006 the TCV is now located on the upside of the spring and its function is controlled by piston speed, not piston position.
“Kashima coating” has been applied to the fork tubes to reduce friction for smoother suspension performance. Front wheel travel is 300mm (11.8″).
The fork pitch (or separating width between the tubes) has been increased for 2006 for improved handling.
Front fork adjustments include: 20-way compression damping and 20-way rebound damping. Optional fork springs are available through Genuine Yamaha parts.
Large, semi-wrap-around plastic fork protectors provide excellent protection from stone / rock chips. The “self-supporting” design helps to reduce friction for smoother fork operation.
Revised Monocross link rear suspension system features a fully adjustable, Kayaba, piggyback shock which provides 315mm (12.4″) of wheel travel and features separate adjusters for high- and low-speed compression damping. Adjustments include: spring preload, 20-way rebound damping, 20-way low-speed compression damping and 2 turns of high speed compression damping.
The damper rod diameter in the 2006 KYB shock has been increased from 16 to 18mm while sub tank capacity has been increased by 30% for improved shock performance, Kashima coating is used in the shock body and sub tank to reduce friction and improve suspension performance during a long moto.
All new, trick titanium shock spring reduces weight by 500 grams. This is a significant weight reduction since it is unsprung weight that has been reduced. A reduction in “unsprung” weight , causes a dramatic effect on suspension performance. The new titanium spring provides outstanding strength, and durability, combined with reduced weight.
The 2006 Kayaba shock utilizes a full rebound oil lock system for excellent suspension function and great ride quality.
250mm floating front disc brake utilizes lightweight, aluminum pistons in its twin piston caliper for excellent stopping power and feel. Shorty style adjustable front brake lever.
245mm rear disc brake with single piston caliper uses an integrated master cylinder (fluid reservoir is integrated into the top of the master cylinder) for strong stopping power with excellent feel and control.
New rear brake caliper not only improves rear braking efficiency but also sits lower on the swingarm to reduce the center of gravity. The new caliper features a new, plastic caliper protector and a 30% lighter lower disc protector.
All new “slim line” body components include: front and rear fenders, rad shrouds, side covers /number plates, and seat. The seat foam has been revised for more cushioning effect and improved rider comfort. The new body design gives the all new 2006 YZ450F a new lighter more modern look plus allowing for fast, easy rider movements.
Specially designed “Sun Star” rear sprocket increases the contact area between the sprocket and chain rollers, thereby reducing the load on the chain and increasing the service life of both chain and sprocket.
Lightweight, 21″ front and 19″ rear Excel rims provide exceptional durability and help reduce unsprung weight for optimal suspension performance and handling.
New rear wheel collar is tapered to allow for faster, easier wheel removal installation.
Lightweight, 21″ front and 19″ rear Excel rims are exceptionally durable and reduce unsprung weight.
Dunlop knobby tires offer competition-spec traction and excellent wear.
New “flat-design” seat features multi density foam that provides good initial softness / comfort and then increases the firmness as more pressure is applied. The seat is raised 10mm for 2006. The “pebble” or “gripper” finish on the top and side surfaces provides excellent rider grip and durability.
New stainless steel coated exterior nuts and bolts for improved appearance.
Large fuel cap and filler hole ensures easy opening and fast, hassle-free refueling.
Lightweight, titanium footpegs provide excellent grip and ground clearance.
Cleated, rear brake lever and folding shift lever tip offer superb grip and exceptional durability.
Stainless steel, inner clutch cable provides excellent strength and long life.
Re-packable exhaust silencer means a rider can maintain optimum engine performance and reduced noise levels.
Rugged engine and water pump protector plates
Engine 4-stroke, DOHC, 5-valve titanium, liquid-cooled
Bore and Stroke 95 x 63.4 mm
Compression Ratio 12.3:1
Maximum Torque 5.4 kg-m (39.1 ft-lb) @ 6,500 rpm
Fuel Delivery Keihin FCR-MX39
Ignition Digital CDI
Final Drive chain
Suspension (Front) Adjustable 48mm inverted fork
Suspension (Rear) Fully adjustable link Monocross
Brakes (Front) 250 mm floating disc
Brakes (Rear) 245 mm disc
Tires (Front) 80/100-21
Tires (Rear) 110/90-19
Length 2192 mm (86.3″)
Width 815 mm (32.1”)
Height 1,298 mm (51.1″)
Wheelbase 1495 mm (58.9″)
Seat Height 986 mm (38.8″)
Dry Weight 99.8 kg (219.6 lb)
Fuel Capacity 7 litres (1.6 Imp. gal.)
Colour(s) Yamaha Blue