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

This article has multiple issues. Please help improve it or discuss these issues

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1. It needs additional citations for verification. Tagged since December 2009.

2. It may need to be rewritten entirely to comply with Wikipedia's quality

standards. Tagged since December 2009.

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.