develops new fuel efficient 700 cc engine. Concurrently they develop a
new large capacity scooter that uses Honda's 2nd generation Dual Clutch
Honda Motorcycles Japan
Honda Motor Co., Ltd. has announced the development of a new
motorcycle engine with powerful torque in the low to mid-speed range and
top class, fuel-efficient performance, along with a second-generation
Dual Clutch Transmission.
This new engine is a liquid-cooled, 700cc, 4-stroke, in-line, 2-cylinder
engine that fits into the mid-class range (displacement between 500 and
750cc) popular in Europe. Fuel economy exceeds 27km/L, best in the
mid-class range, and achieves an approximate 40% improvement over other
sports models in its class.
This new engine can be coupled with a newly developed lightweight,
compact second-generation Dual Clutch Transmission, featuring a smooth,
direct feel and excellent transmission efficiency, in addition a 6-speed
This new engine will be mounted on three models based on different
concepts, which are slated for exhibition at EICMA 2011(69th
International Motorcycle Exhibition) to be held in November in Milan,
Honda developed this new motorcycle engine in order to realise a
set of motorcycles based on its new concept of offering outstanding fuel
efficiency in the mid-class while delivering powerful, throbbing torque
in the normal range for touring and urban riding.
Development was performed to meet these requirements:
An engine that is easy to handle with plentiful torque in the range
normally used, and which also delivers a pleasant, throbbing feel
during sporty rides. Top-class, fuel-efficient environmentally friendly
performance best suited for the next-generation mid-class engine.
- A lightweight, compact design that allows more freedom in the body layout and provides convenient space
- Honda determined the engine layout after examining a variety of
engine types from numerous perspectives and decided on an in-line,
700cc, 2-cylinder engine with a 62º forward lean (cylinder assembly
- To meet a wide variety of uses, two transmissions can be coupled
with this engine: the second generation of Honda's innovative Dual
Clutch Transmission, and a 6-speed manual transmission.
Main Features of the New Engine
Higher combustion efficiency and lower friction
A wide variety of low friction technologies that aid better fuel
economy are incorporated: To improve fuel efficiency through
better-controlled combustion while realising a powerful ride in the low
to mid-rpm ranges, the bore-stroke ratio is set at 73×80mm. An ideal
combustion chamber shape and optimum valve timing also contribute to
achieve stable combustion. Resin coating is applied to the pistons, and
lightweight aluminium material is employed for the first time in a
motorcycle in the friction-reducing roller rocker arm.
Uneven-interval firing and uniaxial primary balancer
Adoption of uneven-interval firing with a 270° phase crank and
uniaxial primary balancer help realise an engine with a pleasant
throbbing feel that also reduces vibration.
Branch intake port inside the cylinder head, valve timing
The layout of a branch intake port inside the cylinder head was
chosen to have only one intake channel for two cylinders. This design
creates deliberate interference between the two cylinders" intake
processes to achieve precisely calculated changes to combustion timing.
In addition, to change the valve timing between the two in-line
cylinders with one camshaft, the specifications provide for a cam with
two timing routines for the intake valve. Through these measures, subtle
combustion changes can be generated to give the engine a delightful,
Exhaust emission purification system
To maximise the efficiency of exhaust emission purification so that
the catalyzer, a three-way catalyst, can be started promptly after the
engine starts, the catalyzer has been placed directly beneath the
exhaust ports. This design lets the combustion gas pass through the
catalyst while the gas is still hot. In addition, a combination of
measures, including the adoption of an electronically-controlled fuel
injection system (PGM-FI), allows the engine to achieve an emission
level approximately half the European emission standards (Euro 3). The
resulting environmental performance is ranked among the top in the world
without compromising powerful, smooth output.
Second-generation Dual Clutch Transmission
The Dual Clutch Transmission, developed for the first time by Honda
for motorcycles and installed on the VFR1200F, is now lighter and more
compact through a simplified hydraulic circuit and other design
enhancements. A learning function has been added to each selected
running mode to detect a variety of riding environments from city
streets to mountain passes and automatically performs the most suitable
shift control. Although it is an automatic transmission, the Dual Clutch
Transmission delivers fuel economy on a par with manual transmissions
as a result of its excellent transmission efficiency.