It looks like Yamaha is very proactive to market the Yamaha FZ16 bike. This article sourced from Yamaha, focusses on educating the
customers about the mid-ship muffler of the FZ16. If you want to read my
first article, click on Yamaha FZ16 Review. So lets look into what Yamaha says about the bike’s main feature.
With the release of the new Yamaha FZ16, India is going to see a bike
with impressive, macho styling never seen before in the Indian market.
It’s a machine packed full of new features that will open the eyes of
Indian customers like its sporty mid-ship muffler, a sturdy-looking
front fork with extra thick 41mm diameter tubes and India first radial
tyre on the rear wheel.
For this article we had a chance to talk with the engineers from
Japan who worked on this model. Their design and engineering locus on
building a bike that would be Fun to Ride. We begin by reporting what
they had to say about the distinctive mid-ship muffler.
The first thing most people will notice when they look at the new
FZ16 is its mid-ship muffler. The term mid-ship means of course at the
middle of the ship, and in this case, means that the muffler is located
closer to the machine’s center of gravity. Is it meant to give the bike
an impressive and distinctive exterior design? We asked the engineers
about its purpose and its actual benefits for the rider.
As you can see, this muffler has a distinctive look that serves to
accentuate the presence of rear tyre and contributes to the machine’s
unique exterior styling. But, at the same time it designed to improve
exhaust performance and to be a major factor contributing to this models
light and natural handling feeling. The muffler is one of the heavier
components on a motorcycle. What’s more, it is a weight that is usually
positioned far away from the engine and off-center to the right or left
of the machine’s center of gravity. So, from the standpoint of an deal
concentration of mass at the center of the machine, a mid-ship muffler
that moves that weight closer to the machine’s center of gravity makes a
big difference. Better concentration of mass means a quicker
convergence of motion resulting from reaction to forces from the road,
which in turn means quicker, lighter handIing.
Is improving the concentration of mass a new design concept?
No, It has long been one of our basic design and engineering ideals. At
Yamaha, our basic design and engineering approach is to look at the
entire machine, including the engine, chassis and all the components, as
a single unit and design it with the aim of achieving a ride that
provides the ultimate sense of rider-machine unity. And, to achieve this
sense of unity with the machine, concentration of mass is an important
key. We have tested mid-ship mufflers on our MotoGP race machines and
our European models YZF-R6 and FZ1 have mid-ship mufflers, the engineers
told us.
Looking at a mid-ship muffler, however, you might think that it has
limited capacity and, thus, limited exhaust performance. And as everyone
knows, limited exhaust performance means limited engine performance. We
asked the Yamaha engineers to tell us more about the product concepts
and the development aims.
The YZF R15
and FZ16 were developed with the aim of going beyond the conventional
commuter bike and to achieve true sports bike performance that offers
the owner the real fun of riding. With the YZF-R we have achieved
performance that can be thoroughly enjoyed not only on the streets but
on a race circuit as well, As for the FZ16, it takes the same sporty
technical concept of the YZF R15 and translates it into a model with
simpler air-cooled engine to create an attractive street machine with
something extra to offer riders. That something extra is a wider band of
powerful torque for truly dynamic performance plus looks the give the
added value of pride of ownership.
Both the FZ16 and YZF-R15 have performance features including a
balancer, rocker roller arm and offset crankshaft. Also things like
optimized piston rings, all for the purpose of improving the three
factors that effect engine performance most: intake/exhaust efficiency,
combustion efficiency and reducing the horsepower loss. The major factor
contributing to an invigorating acceleration feeling and passing
performance in a motorcycle is the optimized inertial mass of the
crankshaft. The relationship between the inertial mass of the crankshaft
and the engine displacement is called the IV ration, arid it is an
important factor effecting drivability. That is why concerted efforts
were made to optimize the IV ratio on the FZ16 along with optimizing the
cap setting. The combined result is acceleration with a good sense of
pulse and strong torque characteristics.
So, what does the mid-ship muffler contribute to the FZ16?
It is said that you need plenty of exhaust pipe length and muffler
capacity. Can this mid-ship muffler really be effective? The exhaust
system is made up of the exhaust pipe, the expansion chamber and the
muffler. This mid-ship muffler has 20% more capacity than the unit on
the Gladiator to provide plenty of silencing effect and performance. The
performance of the exhaust pipe is determined by its diameter, length
and curves, the effectiveness of the expansion chamber is determined by
its volume and shape, while the performance of the muffler depends on
the layout of the pipes and the partitions. Also, since a certain amount
of exhaust pipe length is necessary to achieve the desired engine
performance, a mid-ship muffler has some disadvantages.
For the FZ16, however, an exhaust system with a mid-ship muffler was
chosen in order to help achieve the concentration of mass that would
contribute to light, sportier handling. And, to ensure performance the
exhaust pipe has been given a full 1,500 mm of length, say the Yamaha
engineers. And when you look under the bike you will see that the
exhaust pipe passes through the expansion chamber once and then forms a
loop before entering the chamber again. This is truly a unique and
unprecedented innovation for a model with a single-cylinder engine.
The fact is that there is a pressure pulse created in the exhaust
pipe by the high pressure exhaust gases released by the exhaust valve.
This rush of pressurized gas reflects back from the end of the exhaust
pipe and returns toward the exhaust valve with diminishing strength. The
rhythm of this exhaust pressure pulse depends on the length of the
exhaust pipe. And, as you know, with a 4-stroke engine there is an
overlap in the opening interval of the intake and exhaust valves when
both valves are open.
The exhaust system on this model has been designed to use the
expansion chamber to minimize the effect of this pulse over a wide rpm
range. This increases the intake efficiency, and that ensures plenty of
torque over a broad range from low to high speeds, say the engineers.
With the combined effects of the 1500mm exhaust pipe and an innovative
expansion chamber design, the mid-ship muffler of the Yamaha FZ16 is a
part of an exhaust system that contributes to outstanding combustion
efficiency.
There are also many measures to ensure greater reliability in the
engine. A centrifugal cast Aluminum cylinder has been adopted for the
first time on a Yamaha engine. This production method involves making
the cast iron sleeve by the centrifugal casting method in order to give
it a surface with slight indentations and protrusions that greatly
improves the tightness of the fit between the sleeve and the Aluminum
cylinder.
The tighter, more complete fit provides excellent heat dissipation.
Another thing we did to contribute to improved cooling effect besides
simply increasing the size of the cooling fins was to design a package
that directs the running air flow so it cools the engine more
effectively. This package includes an air scoop which is used to direct
air flow more effectively at the cylinder head, the Yamaha Ram-Air Cooling System (YRCS) that sends cooling air to the spark plug area, plus other measures, they say.
In other words, this engine and the mid-ship muffler it is mounted
with give this model three strong benefits. The engine is designed to
provide plenty of torque from low speeds all the way up to the
high-speed range, and the mid-ship muffler improves the concentration of
mass to help provide a very high level of handling stability while also
giving the bike a very distinctive appearance. There are also several
other measures taken in this model’s design to improve the concentration
of mass, including adoption of air cooling, adoption
of a 20-degree forward-inclined cylinder (25-degree on the Gladiator),
adoption of lightweight wheels, lightweight radial tyre, Aluminum
handlebar crown, lightweight headlight, plastic resign chain cover and
the adoption of a Monocross suspension. ln the next article we will
focus on the radial tyre.
I hope you enjoyed the article. It seems the next article will be
about the radial tyres of Yamaha FZ16. Will keep you posted. Article,
courtesy of Yamaha.
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