New shape combustion chamber with 4-valve head design

As already mentioned, Yamaha’s engineers have focused on air intake volume control and intake efficiency as the key areas in the development of the new R1 engine. The adoption of YCC-I and YCC-T are complemented by the introduction of an all-new cylinder head which is designed to work in close harmony with the new G.E.N.I.C.H. technologies in order to achieve our goal of increased performance at all engine speeds.

The use of YCC-I and YCC-T have transformed the operation of the new generation engine, and in order to maximise the gains offered by this new technology, the cylinder head design has been completely revamped. In order to complement the new electronic intake and throttle control technologies, virtually every aspect of the 2007 cylinder head layout is new.

The R1’s reshaped combustion chamber runs with a higher compression ratio of 12.7:1, and the valve angle has been revised to 24 degrees – the same angle that is used on the 2006 R6.

For 2007 the R1 utilises an all-new four-valve cylinder head design developed from the advanced technology seen on our YZR-M1 MotoGP race bike, and features two 31mm diameter intake valves, and two 25mm exhaust valves. The two intake valves are manufactured from titanium for reduced reciprocating weight, which promotes the increased intake valve lift featured on the 2007 engine. And to ensure efficient high-rpm operation, the R1 runs with lightweight VX alloy valve springs which are designed to handle continuous high-load riding conditions.

These changes to the cylinder head design maximise the benefits of the new YCC-I and YCC-T by ensuring greater air intake volume at all engine speeds. In addition, the revised valve configuration and angle give reduced valve recess compared to the 2006 model, which makes for a smoother piston head shape. The result is extremely high levels of combustion efficiency which contribute greatly to the new engine’s stronger and more linear performance throughout its wide operating range.

New slipper clutch

The new R1 is designed to deliver the ultimate supersport experience on both the road and circuit, and in order to ensure a smoother approach to the apex of turns, a slipper clutch is fitted. This system shares the same structure as that found on the limited-edition 2006 YZF-R1SP model, and is designed to limit the amount of back-torque transmitted from the rear wheel through to the crank. This race-developed system improves traction during rapid deceleration and hard braking, and enhances engine and transmission reliability.

New design dual elliptical mufflers

The 2007 R1 is equipped with a completely redesigned exhaust system featuring an optimised length, expansion chamber and pipe sizes, while the new-shape mufflers have a fresh and impressive appearance. The mufflers’ cross section is an oblate elliptical shape which appears to lift the rear cowl, giving the higher-powered fifth-generation R1 a more masculine and aggressive profile. From the rear, the mufflers form a V-configuration to give this remarkable new bike a unique looking tail-end.

High performance ignition coils

Spark energy has been increased by a re-evaluation of the coil resistance, and the addition of magnets to the coils helps to reduce magnetic saturation.

3-way catalyser with oxygen sensor

A new 3-way catalyser with oxygen sensor not only reduces emissions, it also helps to achieve excellent fuel economy. The new system features platinum and rhodium elements in a honeycomb-shaped catalyser. The system’s efficiency is further improved by the addition of an oxygen sensor which feeds information to the ECU, which can instantaneously adjust fuel supply to ensure optimum combustion efficiency for improved performance and cleaner emissions.

Engine Technical Highlights

• New liquid-cooled 4-stroke in-line 4-cylinder engine
• Bore x stroke 77 x 53.6mm
• Higher 12.7:1 compression ratio
• New YCC-I (Yamaha Chip Controlled Intake) variable intake funnel – the first ever electronically-controlled motor-driven system on a production motorcycle
• New YCC-T (Yamaha Chip Controlled Throttle) electronic throttle
• New 4-valve cylinder head design
• Titanium intake valves
• Redesigned combustion chamber
• Slipper clutch
• Reshaped dual upswept mufflers
• High performance ignition coils
• 3-way catalyser with oxygen sensor
• Closed-deck cylinder
• Liner-less plated cylinder
• FS (Fracture Split) connecting rods
• More efficient Forced Air Intake system
• Compact EXUP with titanium valves
• New-shape twin-fan radiator