NATHUSARI NATHUSARI CHOPTA CHOPTA (SIRSA) (SIRSA) PROJECT REPORT PROJECT REPORT ON ON HERO HONDA HERO HONDA
Oct 28, 2014
NATHUSARI CHOPTA (SIRSA)NATHUSARI CHOPTA (SIRSA)
PROJECT REPORTPROJECT REPORT
ONON
HERO HONDAHERO HONDA
Submitted to:- Submitted by:-
Mr. Rajender Sharma Kamlesh Kumar
H.O.D. Mech. Engg. Mech. Engg. 5TH Sem.
Roll no: - 10029170012
Hero Honda's company profile
The joint venture between India's Hero Group and Honda Motor Company, Japan
has not only created the world's single largest two wheeler company but also one
of the most successful joint ventures worldwide.
During the 80s, Hero Honda became the first company in India to prove that it was
possible to drive a vehicle without polluting the roads. The company introduced
new generation motorcycles that set industry benchmarks for fuel thrift and low
emission. A legendary 'Fill it - Shut it - Forget it' campaign captured the
imagination of commuters across India, and Hero Honda sold millions of bikes
purely on the commitment of increased mileage.
Over 20 million Hero Honda two wheelers tread Indian roads today. These are
almost as many as the number of people in Finland, Ireland and Sweden put
together!
Hero Honda has consistently grown at double digits since inception; and today,
every second motorcycle sold in the country is a Hero Honda. Every 30 seconds,
someone in India buys Hero Honda's top -selling motorcycle – Splendor. This
festive season, the company sold half a million two wheelers i n a single month—a
feat unparalleled in global automotive history.
Hero Honda bikes currently roll out from its three globally benchmarked
manufacturing facilities. Two of these are based at Dharuhera and Gurgaon in
Haryana and the third state of the art manufacturing facility was inaugurated at
Haridwar, Uttrakhand in April this year. These plants together are capable of
producing out 4.4 million units per year.
Hero Honda's extensive sales and service network now spans over 3000 customer
touch points. These comprise a mix of dealerships, service and spare points, spare
parts stockiest and authorized representatives of dealers located across different
geographies.
Hero Honda values its relationship with customers. Its unique CRM initiative -
Hero Honda Passport Program, one of the largest programs of this kind in the
world, has over 3 million members on its roster. The program has not only helped
Hero Honda understand its customers and deliver value at different price points,
but has also created a loyal community of brand ambassadors.
Having reached an unassailable pole position in the Indian two wheeler market,
Hero Honda is constantly working towards consolidating its position in the market
place. The company believes that changing demographic profile of India,
increasing urbanization and the empowerment of rural India will add millions of
new families to the economic mainstream. This would provide the growth ballast
that would sustain Hero Honda in the years to come. As Brijmohan Lall Munjal,
the Chairman, Hero Honda Motors succinctly points out, "We pioneered India's
motorcycle industry, and it's our responsibility now to take the industry to the
next level. We'll do all it takes to reach there.''
HERO HONDA. 'S MISSION
Hero Honda’s mission is to strive for synergy between technology, systems and
human resources, to produce products and services that meet the quality,
performance and price aspirations of its customers. At the same time maintain the
highest standards of ethics and social responsibilities
This mission is what drives Hero Honda to new heights in excellence and helps the
organization forge a unique and mutually beneficial relationship with all its stake
holders.
HERO HONDA'S MANDATE
Hero Honda is a world leader because of its excellent manpower, proven
management, extensive dealer network, efficient supply chain and world-class
products with cutting edge technology from Honda Motor Company, Japan. The
teamwork and commitment are manifested in the highest level of customer
satisfaction, and this goes a long way towards reinforcing its leadership status.
HEROHONDA BIKE MODELS
Model: Achiver ES Model: Achiver Kick Start Model: CBZ Xtreme ES
Model: CBZ Xtreme Kick Start Model: CD Dawn Model: CD Deluxe
Model: Glamour Electric Start Model: Glamour FI ES Model: Glamour FI Kick Start
Model: Glamour Kick Start Model: Hunk ES Model: Hunk Kick Start
Model: New Karizma Model: Passion Plus Model: Pleasure
Model: Splendor NXG (Alloy) Model: Splendor NXG (Spoke) Model: Splendor Plus
Model: Super Splendor Model: Ambition Model: CBZ
Model: CBZ* Kick Start Model: CBZ* Electric Start Model: CD 100 SS
Model: Dawn Model: Karizma Model: Passion
Model: Splendor Model: Street Dlx Model: Super Splendor KS
HERO HONDA KARIZMA
Jet Set Go...
Hero Honda
Karizma was the
first real sports bike
in India. The bike
addresses to those
who have a passion
for speed and
styling and head-
turning looks. It
has 17 ps power
thrust and picks up
0-60 in 3.8 heart-
stopping seconds.
The bike is based
on power and
styling. Disc breaks
and Mag wheels
makes Karizma the
safest jet on the
road.
Company
Stroke Maximum Power Displacement
Hero Honda
Motors Ltd.4-Stroke 16.8 bhp @ 7000 rpm 223 cc
Striking Features
1. Style
2. Sporty position of the seat.
3. It stands on its feet even at speeds reaching up to 130 kmph.
4. Fuel Efficiency.
Color Variants
1. Pearl Composed Red
2. Myth Gold Metallic
3. Sparkling Silver
4. Turquoise Blue
5. Candy Blazing Red
6. Black
7. Moon Yellow
Price Tag - Rs 79,000 Ex-Showroom in Delhi
(The prices are to the close approximation. Please check the latest prices and
variant specifications with your dealer.)
Technical Specifications
Dimension & Weight
Overall height 1160 mm
Overall length 2125 mm
Overall Width 755 mm
Wheelbase 1355 mm
Ground Clearance 150 mm
Kerb weight 150 kg
Fuel Tank Capacity 15 litres
Engine
Type OHC, Air Cooled
Stroke (2/4) 4-stroke
No. of cylinders Single Cylinder
Displacement 223cc
Electrical 12 V, 7.0 Ah
Transmission
No. of Gears 5 speed
Clutch Multi-plate wet type
Performance
Maximum Power 16.8bhp @ 7000rpm
Max. Torque -
Start Kick / Electric
Suspensions
Front Telescopic Hydraulic Shock Absorbers
RearSwing arm with 5 step adjustable type hydraulic
shock absorber
Brakes
Front Disc Brakes, 276 mm diameter
Rear Internal Expanding Shoe, 130 mm
Tyres
Front 2.75 x 18” - 42 P
Rear 100 / 90 x 18” - 56 P
Motorcycle Engine
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A motorcycle engine is an engine that powers a motorcycle.
Motorcycle engines may be two stroke or four stroke, reciprocating or Wankel,
single-cylinder or multicylinder (if reciprocating), or single-rotor or twin-rotor (if
Wankel). The engine typically drives the rear wheel, but some small bikes such as
the Velosolex have a friction drive to the front wheel. Most engines have a gearbox
of between two and six ratios, and some heavy cruisers even have a reverse gear.
Power is sent to the driven wheel by belt, chain or shaft. In Europe, up till 1970,
engine capacities typically ranged from about 50cc to 750cc; but since then
machines with capacities up to 2000cc have become common. In the USA,
motorcycles with large capacities have been common for much longer.
Even today, most motorcycles still bear some resemblance to early motorised
bicycles, so the engine is normally found where the crank-wheel would be on a
pedal bicycle. However, some early examples had the engine within the driven
wheel, and the Velosolex has its engine ahead of the handlebars, just above the
front wheel.
Types
Almost all production motorcycles have gasoline (UK petrol) internal combustion
engines. Both four-stroke and two-stroke engines are used, but strict emission laws
have led to far fewer two-strokes. A few have used Wankel rotary engines, but no
Wankel bikes are currently in production. Small motorcycles are air-cooled, but oil
cooling or water cooling is more usual with larger machines. Some scooters use
batteries and an electric motor. (The 2009 TT races introduced a new category
'TTX' for electric bikes using fuel-cells or batteries).
Most motorcycle engines are mounted transversely, with the crankshaft across the
frame, but others have the crankshaft longitudinal, along the frame. Transverse
engines usually have chain or belt final-drive, while longitudinal mounting is more
suitable for shaft final-drive.
Motor scooters have the engine as part of the rear suspension, so the engine not
fixed rigidly to the main frame. Instead, the combined engine-transmission-
swingarm assembly is pivoted to follow the road surface and is part of the
"unsprung weight". The chain final-drive of scooters runs in an oil-bath within the
engine casings. "Step-throughs" motorcycles may have a rigidly fixed engine, or
may have a scooter-type arrangement.
Two-stroke and four-stroke
Two-stroke engines have fewer moving parts than four-stroke engines, and
produce twice the number of power strokes; consequently, two-stroke engines are
more powerful for their mass. Two-strokes offer stronger acceleration, but similar
top speed compared to a four-stroke engine. They are also easier to start.Two-
stroke engines have shorter life due to poorer piston lubrication, since lubrication
comes from the fuel-oil mix.
Four-stroke engines are generally associated with a wider power band making for
somewhat gentler power delivery, but technology such as reed valves and exhaust
power-valve systems has improved ride-ability on two-strokes. Fuel economy is
also better in four-strokes due to more complete combustion of the intake charge in
four-stroke engines.
Nevertheless, two-strokes have been largely replaced on motorcycles in developed
nations due to their environmental disadvantages. Cylinder lubrication is
necessarily total-loss and this inevitably leads to a smokey exhaust, particularly on
wide throttle openings. Two-stroke engined motorcycles continue to be made in
large numbers, but mostly low power mopeds, small scooters and step-through
underbones where they still compete strongly with four-strokes (including the
highest selling motorcycle of all time, the 50 cc Honda Super Cub). The major
markets of two-stroke motorcycles are in developing nations.
Cylinder Heads (Four Stroke)
Cylinder head design has a significant effect on the efficiency of combustion, and
thence the power output of the engine. The head may be flat, in which case the
combustion chamber resides within the cylinder and/or a depression in the piston
crown, but usually a "dome" within the cylinder head provides most of the
combustion volume. In motorcycles, valve gear tends to be side valve, overhead
valve (ohv) with pushrod operation, (single) overhead cam, (s)ohc, and double
overhead cam, dohc. An ohc (or dohc) cylinder head will have at least two valves
per cylinder (1 inlet & 1 exhaust), but some have three (2 inlet & 1 exhaust), or
four (2 inlet & 2 exhaust), or even five (3 inlet & 2 exhaust). Cylinder heads are
the hottest part of the engine and require adequate cooling, typically air cooling, oil
cooling or liquid cooling.
Some motorcycles such as Harley-Davidsons, Moto Guzzis and BMWs become
identifiable by their cylinder-head types, namely airhead, panhead, oilhead, and
even knucklehead [4][6]. The Ducati desmos head enables higher rpm to be achieved
without the danger of "valve bounce".
Valve control (Four Stroke)
In a side-valve engine, the valves are operated from the "underhead" cam without
special valve gear. OHV engines have valves operated by pushrods. OHC &
DOHC engines have overhead camshafts typically operated by chain, belt, gear
train or bevel gear drive.
Honda equipped the CBR400F with REV ( described as "revolution responding
type valve pausing mechanism") in 1983,[7] This system enabled to switch over the
number of valve operations per cylinder between low and medium speed
revolution range and high speed revolution range. In 2002, Honda introduced
HYPER VTEC in the VFR800 Interceptor. In 2006, Kawasaki introduced VVT in
the Concours 14..
Four-stroke engine
Four-stroke cycle used in gasoline/petrol engines. The right blue side is the intake
and the left yellow side is the exhaust. The cylinder wall is a thin sleeve
surrounded by cooling liquid.
A four-stroke engine, also known as four-cycle, is an internal combustion engine
in which the piston completes four separate strokes—intake, compression, power,
and exhaust—during two separate revolutions of the engine's crankshaft, and one
single thermodynamic cycle.
There are two common types of engines, which are closely related to each other
but have major differences in their design and behavior. The earliest of these to be
developed is the Otto cycle engine which was developed in 1876 by Nikolaus
August Otto in Cologne, Germany[1]. This engine is most often referred to as a
petrol engine or gasoline engine, after the fuel that powers it.[2] The second type of
four-cycle engine is the Diesel engine developed in 1893 by Rudolph Diesel, also
of Germany. Diesel created his engine to maximize efficiency which was lacking
in the Otto engine. There are several major differences between the Otto cycle
engine and the four cycle diesel engine. The diesel engine is made in both a two-
cycle and a four-cycle version. Ironically Otto's company Deutz AG produces
primarily diesel engines in the modern era.
The Otto cycle is named after the 1876 engine of Nikolaus A. Otto, who built a
successful four-cycle engine which was based on the work of Jean Joseph Etienne
Lenoir. It was the third engine type that Otto developed. It used a sliding flame
gateway for ignition of its fuel which was a mixture of illuminating gas and air.
After 1884 Otto also developed the magneto allowing the use of an electrical spark
for ignition, which had been unreliable on the Lenoir engine.
Today, the internal combustion engine (ICE) is used in motorcycles, automobiles,
boats, trucks, aircraft, ships, heavy duty machinery, and in its original intended use
as stationary power both for kinetic and electrical power generation. Diesel engines
are found in virtually all heavy duty applications such as trucks, ships,
locomotives, power generation, and stationary power. Many of these diesel engine
are two cycle with power ratings up to 105,000 hp (78,000 kW).
The four cycles refer to intake, compression, combustion (power), and exhaust
cycles that occur during two crankshaft rotations per power cycle of the four cycle
engines. The cycle begins at Top Dead Centre (TDC), when the piston is farthest
away from the axis of the crankshaft. A cycle refers to the full travel of the piston
from Top Dead Centre (TDC) to Bottom Dead Centre (BDC). (See Dead centre.)
1. INTAKE stroke: on the intake or induction stroke of the piston , the piston
descends from the top of the cylinder to the bottom of the cylinder, reducing
the pressure inside the cylinder. A mixture of fuel and air, or just air in a
diesel engine, is forced by atmospheric (or greater) pressure into the cylinder
through the intake port. The intake valve(s) then close. The volume of
air/fuel mixture that is drawn into the cylinder, relative to the volume of the
cylinder is called, the volumetric efficiency of the engine.
2. COMPRESSION stroke: with both intake and exhaust valves closed, the
piston returns to the top of the cylinder compressing the air, or fuel-air
mixture into the combustion chamber of the cylinder head.
3. POWER stroke: this is the start of the second revolution of the engine.
While the piston is close to Top Dead Center, the compressed air–fuel
mixture in a gasoline engine is ignited, usually by a spark plug, or fuel is
injected into the diesel engine, which ignites due to the heat generated in the
air during the compression stroke. The resulting massive pressure from the
combustion of the compressed fuel-air mixture forces the piston back down
toward bottom dead centre.
4. EXHAUST stroke: during the exhaust stroke, the piston once again returns
to top dead center while the exhaust valve is open. This action evacuates the
burnt products of combustion from the cylinder by expelling the spent fuel-
air mixture out through the exhaust valve(s).
PISTON
A piston is a component of reciprocating engines, reciprocating pumps, gas
compressors and pneumatic cylinders, among other similar mechanisms. It is
the moving component that is contained by a cylinder and is made gas-tight by
piston rings. In an engine, its purpose is to transfer force from expanding gas in
the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump,
the function is reversed and force is transferred from the crankshaft to the piston
for the purpose of compressing or ejecting the fluid in the cylinder. In some
engines, the piston also acts as a valve by covering and uncovering ports in the
cylinder wall.
Piston engines
There are two ways that an internal combustion piston engine can transform
combustion into motive power: the two-stroke cycle and the four-stroke cycle. A
single-cylinder two-stroke engine produces power every crankshaft revolution,
while a single-cylinder four-stroke engine produces power once every two
revolutions. Older designs of small two-stroke engines produced more pollution
than four-stroke engines. However, modern two-stroke designs, like the Vespa ET2
Injection utilise fuel-injection and are as clean as four-strokes. Large diesel two-
stroke engines, as used in ships and locomotives, have always used fuel-injection
and produce low emissions. One of the biggest internal combustion engines in the
world, the Wärtsilä-Sulzer RTA96-C is a two-stroke; it is bigger than most two-
storey houses, has pistons nearly 1 metre in diameter and is one of the most
efficient mobile engines in existence. In theory, a four-stroke engine has to be
larger than a two-stroke engine to produce an equivalent amount of power. Two-
stroke engines are becoming less common in developed countries these days,
mainly due to manufacturer reluctance to invest in reducing two-stroke emissions.
Traditionally, two-stroke engines were reputed to need more maintenance (despite
exceptions like the Ricardo Dolphin engine, and the Twingle engines of the Trojan
car and the Puch 250 motorcycle). Even though the simplest two-stroke engines
have fewer moving parts, they could wear out faster than four-stroke engines.
However fuel-injected two-strokes achieve better engine lubrication, also cooling
and reliability should improve considerably
1. Pumps :Piston pumps can be used to move liquids or compress gases.
GEAR BOX WORKING
For you 'super wrenches' out there who can split an engine case and rebuild a
motorcycle transmission blindfolded this page is going to seem like a nearly
criminal over simplification of how the gearbox functions. You'll be correct, it is.
This page is only meant to provide a basic understanding of how a motorcycle
transmission is operating so riders know what's happening when they hear 'gears'
(we'll sort that out in a moment) grinding and the transmission is doing quirky
things.
Now the meat and potatoes of this page.
Most manual transmissions are called "constant mesh" which simply means all of
the gears in the box are constantly in contact with each other. When you shift
gears you aren't actually moving any gears. You're moving a plate or a cylinder
that locks into the side of a gear engaging the output shaft with that gear.
Check out the animation below
Animation courtesy Mike Challenger, Haydndesign ltd.
What you're looking at:
The violet shaft is the "input" shaft from the engine. This isn't actually the
crankshaft. The input and crank shafts are separated by the clutch. Notice the blue
gear attached to the input shaft is turning a gray gear. At this point that gear is not
'engaged' so the bike is in neutral
The green cylinder is a barrel shaft that's rotated by a ratchet mechanism (what
you're actually moving when you raise or lower your shift lever) Notice as the
animation starts that shaft rotates and moves the fork. As the fork moves it pushes
the gold colored disk (with holes in it) toward the gear (with dogs that fit into those
holes) and drive is engaged.
Once engaged the yellow output shaft turns and you're now moving down the
road.
In a transmission with more than one forward gear that shift fork would move back
and forth, alternately disengaging from one gear and engaging another so you'd
have a 1-2 shift. For a 3-4 shift the fork would move to a central position,
disengaging the 1-2 gears and another fork would engage 3rd and then 4th gears.
Now that you understand what's
happening inside the transmission
take another look at that first
animation. Notice the 'pegs' on that
gray gear? Those are called "dogs"
for reasons not transmitted (ha, see what I did there?) the 'dogs' as shown in the
picture (left) are a part of the driven gear just as shown in the animation. The holes
are in the slider shown in the picture (right). When that slider is moved by the shift
fork the holes slide over the dogs and the output shaft begins spinning.
If you're shifting properly, matching engine/transmission speeds and shift quickly
those dogs can slip right into the slots no muss no fuss. If, however, you are a
little lazy with a shift and take too long or don't put much pressure on the shift
lever those dogs will just skitter over the top of the slots causing what many riders
misinterpret as grinding 'gears'.
There are two common problems that develop with motorcycle transmissions.
1. Each time the dogs are allowed to grind the rider is wearing just a little bit off of
them. Those 'pegs' get shorter and shorter (or the holes become more elongated)
until the transmission will no longer stay in a particular gear or it pops out of a
gear. This is 'most' common between 1st and 2nd gear for some reason.
2. The rider forces the transmission to shift too quickly and/or puts too much
pressure on the shift lever. When this happens the dogs might be pressed hard
against the gear in the solid space between slots. Look at the top animation again
and notice the green shift fork. That fork can be bent and, as you can see from the
animation if the fork is bent backward (to the right in this picture) it probably isn't
going to completely engage the dogs. Result, the transmission will pop out of
gear. If the dogs just barely release you'll not only be back in neutral but could
hear a lot of grinding with the dogs rubbing against the slots.
Either way the fix is the same. You have to go inside the transmission case and
replace the broken parts. In the case of most metric motorcycles that means
pulling the engine and splitting the case to gain access to the transmission. Most
Harleys, custom bikes and some BMW's have a separate transmission which can be
removed from the bike independent of the engine and serviced.
Now that you have the 'theory' here's a picture of an actual (BMW) motorcycle
transmission so you can pick out the parts discussed above.
See how the shift forks are moved back and forth by grooves in the shift cam?
That cam is ratcheted one direction or the other based on whether you are up
shifting or down shifting. The cam is the reason you can't skip a gear and just go
from first to third or third to fifth as you can in most cars. Again, I have
oversimplified to an extreme degree but hopefully riders now have some idea
what's going on inside the gearbox.
Carburator Theory and Tuning
For some reason everyone seems to think tuning a carb is just real easy. Change a
jet or two and boom, your there. Yeah, right ! There are quite literally millions and
millions of jet combinations. A rough check on Bing carbs shows there are at least
13,860,000 different combinations of jets. If you are going to change carbs you'd
better be prepared to spend some time and money on the job.
If you look at a carburetor, you will notice a rather large hole
going from one side to the other. This is called a Venturi. Air
passes into the engine through this hole (Venturi). As the
velocity of the air entering the carb (and then the engine)
increases, it's pressure decreases, creating a low pressure or
vacuum in the venturi. This vacuum moves around in the venturi, as the throttle is
opened, and sucks gasoline through the different jets in the carb. The gas then
mixes with the air going through the venturi. The way the jets are made causes the
fuel to vaporize as it goes into the venturi. Where the jets are placed in the carb and
where the jet's outlet is located in the venturi, determines what part of the throttle
opening that jet controls. The idle jet system (comprised of pilot air jet, pilot fuel
jet and pilot fuel screw) controls from 0% to about 25% of the throttle opening.
The throttle valve controls 0% to 35% of the throttle opening. The needle jet and
jet needle control from 15% to 80% of the throttle opening and the main jet
controls 60% to 100%. This means that when you open the throttle about one
eighth of the way open, all of the gas/air mixture going into your engine is
controlled by the idle jet. As you can see, the different jets over lap the operating
range of each other. That is, the jet needle starts to effect things before the effect of
the idle jet ends. This is something to remember when working on carbs...
everything is interconnected. Change one thing and it will effect other things.
OK, let's go over the different systems in the carb and see what they do.
1. Fuel level. The fuel level is controlled by the fuel floats and the fuel float
valve. The floats are hollow or made of something that will float on
gasoline, such as cork. Part of the float presses against the float valve,
sometimes called a needle and seat. Most times the part of the float that
touches the float valve needle is bendable so you can adjust the level of the
fuel in the floatbowel. All plastic floats are not adjustable. If this level is
way too high, gas can leak out the carb overflow tube or into the engine. If
fuel gets into the engine it will thin out the engine oil, ruining it's ability to
lubricate. This will, sooner or later, blow up your engine ! If a full tank of
gas in the evening turns into a half tank by morning, check your oil. If it's
thin and smells like gas, change it and replace your float valve and/or check
your fuel level. If the oil is OK, check under the overflow tube. If it's OK,
then check where you are parking your bike 'cuse someone is walking away
with your gas !
If your fuel level is just a bit high, the mixture will tend to be a bit rich. If it's
low, the mixture will tend to be a bit lean. This is because a high level takes
less vacuum to suck fuel into the engine and a low level takes more vacuum
to do the same.
2. Pilot or idle jet system. The idle jet controls the idle and on up to quarter
throttle, give or take a bit. On some carbs, like Mikuni there is an air jet too.
In conjunction with the idle jet there is an idle jet air screw. This screw leans
or richens the fuel mixture for a smooth idle and on up to one quarter
throttle. From the idle jet, there are little passages cast into the carb that lead
to holes just in front of the throttle valve or plate. There can be just one hole
or there can be several, depending on the carb design. They effect the
mixture as long as the vacuum, in the venturi, is over them. As the throttle
opens further, the vacuum moves to the needle jet and jet needle.
3. The Throttle Valve. The big slide that opens and closes your throttle has a
bevel angle cut in one side of the big round (can be flat, too) slide, toward
the air cleaner. This angle comes in several sizes and helps control the fuel
mixture from idle to about 35% open throttle.
4. Needle Jet. This jet doesn't really even look like a jet, but it is ! It controls
the fuel mixture from 15% to 60% open throttle. It sets in the center of the
carb, right over the main jet.
5. Jet Needle. This is the needle that rides in the throttle slide and goes into the
needle jet. This needle controls the fuel mixture from 20% to 80% open
throttle. It can come in many different sized tapers. Sometimes, one needle
can have several tapers on it. The top end of the needle has grooves cut in it,
usually five, and you can move the little clip on the end up or down to lean
(down) or richen (up) the mixture. Most late model bikes have needles with
only one groove cut in them. This is so you can't richen the mixture, thereby
keeping the EPA happy.
6. Main Jet. This jet controls the fuel mixture from 60% to 100% open throttle.
We want nice clean acceleration from idle to full throttle, with no stumbling or flat
spots. This can be quite a tall order if we are starting with a new carb. Actually, it
can be a real challenge to get things to carburate right after something as simple as
an exhaust pipe change.
Now, I wish I could tell I'm the great carb man, but, well... no one has ever been
dumb enough to hire me to really work over a carb. Well, there was that one time
with that Kaw 650 and aftermarket pipes. It had some kind of weird stock carbs
that looked like Mikunis but really were not. It had TDK or KDT or DTK,
something like that, carbs. It had aftermarket exhaust pipes and was running too
lean, and stumbled at one point under acceleration. Worthless pig ! The jet needles
where not adjustable, so I put little washers under the needle clip, to raise the
needles. The main jet only came in one size, so I drilled it out with ity-bity,
expensive, jet drills. I could move the miss around, but I could not get rid of it.
From the beginning I told the guy it wouldn't work and that he was wasting his
money, and that at the least we needed carbs we could get parts for, but nooo. Just
rise the needles, drill the jets he said... $200 later he finally gave up. I guess I
shouldn't complain, I did get paid... but !
But you want to try it, don't you ? OK, the drill really isn't that hard. Simply run
the engine at whatever throttle opening you want to test, for a mile or so, and look
at the spark plug. Is the spark plug reading lean or rich ? Now look for the jet that
controls that particular throttle opening and exchange it for a richer or leaner one.
Now that doesn't sound very hard, does it ? Oh yes, the throttle transition from one
jet to the next must be smooth too ! Go back over the areas that each jet controls.
They overlap each other. Some a little, some a lot. Make sure you have a good
selection of jets ! Most carb manufacturers have tables of specifications on the jet
needles and needle jets, and other jets that you will find very useful. With these
specs you can make a better guess as to what jet will work best. Some places use
motorcycle dynamometers for testing. These can be a big help to get real close to
the best jet setting. Working out the best main jet for a 170 MPH bike can be quite
unhealthy if you only have a freeway to test on ! Just remember one thing. A
dynamometer is not the real world. A fact more then one factory has found out the
hard way when their super hot, dyno tested, race machines didn't run so fast in the
real world, on real pavement, in real air with real bugs on the windscreen !
Anyway, what I'm trying to get over to you is that just because your buddy said he
got new carb, changed a jet or two and now his bike gets 100 miles per gallon and
has double the horse power, doesn't mean you can too ! It just might require a lot
more work than you bargained for.
Look on the bright side. Carbs used to be real simple at the turn of the century, but
they didn't work as good as today's carbs.
Oh, one last thing, seeing how we are talking carb theory. When an engine is cold,
like when you first start it up. It doesn't evaporate the gas well. Liquid gas does not
burn, so you have to put in lots of gas, because a lot of it does not vaporize. The
choke helps the carb to put into the engine a very rich mixture, and at least some of
that mixture will vaporize and burn.
I had one guy tell me that the reason for a rich mixture when starting was so the
pistons would be lubed by the raw gas and spin the engine over easier so it would
start ! He felt very strongly about this, so I didn't say a thing. Like the Bible says,
don't cast your pearls before swine.
Clutch
Clutch for a drive shaft: The clutch disc (center) spins with the flywheel (left). To
disengage, the lever is pulled (black arrow), causing a white pressure plate (right)
to disengage the green clutch disc from turning the drive shaft, which turns within
the thrust-bearing ring of the lever. Never will all 3 rings connect, with no gaps.
Single, dry, clutch friction disc. The splined hub is attached to the disc with springs
to damp chatter.
A clutch is a mechanical device which provides for the transmission of power (and
therefore usually motion) from one component (the driving member) to another
(the driven member). The opposite component of the clutch is the brake.
Clutches are used whenever the ability to limit the transmission of power or motion
needs to be controlled either in amount or over time (e.g., electric screwdrivers
limit how much torque is transmitted through use of a clutch; clutches control
whether automobiles transmit engine power to the wheels).
In the simplest application clutches are employed in devices which have two
rotating shafts. In these devices one shaft is typically attached to a motor or other
power unit (the driving member) while the other shaft (the driven member)
provides output power for work to be done. In a drill for instance, one shaft is
driven by a motor and the other drives a drill chuck. The clutch connects the two
shafts so that they may be locked together and spin at the same speed (engaged),
locked together but spinning at different speeds (slipping), or unlocked and
spinning at different speeds (disengaged).
Motorcycles typically employ a wet clutch with the clutch riding in the same oil as
the transmission. These clutches are usually made up of a stack of alternating plain
steel and friction plates. Some of the plates have lugs on their inner diameters
locking them to the engine crankshaft, while the other plates have lugs on their
outer diameters that lock them to a basket which turns the transmission input shaft.
The plates are forced together by a set of coil springs or a diaphragm spring plate
when the clutch is engaged.
On most motorcycles the clutch is operated by the clutch lever located on the left
handlebar. No pressure on the lever means that the clutch plates are engaged
(driving), while pulling the lever back towards the rider will disengage the clutch
plates through cable or hydraulic actuation, allowing the rider to shift gears or
coast.
Racing motorcycles often use slipper clutches to eliminate the effects of engine
braking which, being applied only to the rear wheel, can lead to instability.