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hiya, im not really new to riding quads but i am new to owning my own (working) quad. i have a falcon 150, which isnt too bad, bit sluggish on steep inclines but overall far better than the smc r100 i used to own. i have a basic understanding of single cylinder bikes and a less than useful understanding of anything bigger so i may be asking for a lot of help lol. anyway, i look forward to being proved wrong relentlessly and actually maintaining a working bike
Whether carbureted or injected, the fuel system is designed to provide the optimum mixture of air and fuel to the engine under varying conditions. This optimum air/fuel ratio (do not call it the fuel/air ratio!) is called the stoichiometric ratio and in theory is approximately 14.7 parts of air to 1 part gasoline (14.7:1) based on weight, not volume. However, this air/fuel ratio must be modified under different atmospheric and running conditions. A ratio numerically higher than 14.7 would be considered a lean air/fuel mixture, numerically less than 14.7 would be considered a rich mixture.
There are several principles of physics that affect the design of carburetors. Among these are;
a liquid will take the shape of the container it is in
liquids are not compressible
liquid in two containers joined with a passageway will be at the same level if the atmospheric pressure above them is the same
air will flow from a high pressure area to a low pressure area to try and equalize the imbalance
air flowing through a restriction in a passageway (the venturi of a carburetor) will increase in speed and decreases in pressure at the point of restriction
a liquid can be atomized and vaporized
There are three basic types of carburetors, fixed venturi, mechanical slide and constant velocity (CV). Despite their differences, they all use the Venturi Principle which states that air flowing through a restriction will increase in speed and decrease in pressure. It is the decrease in pressure in the carburetor venturi that allows atmospheric pressure to push fuel into the venturi through passageways that are machined into the carburetor body. These passageways contain jets that control the amount of flow through them.
In order to burn properly and efficiently, the fuel must be first atomized (broken down into a fine mist) and then vaporized, that is, changed from a liquid to a vapor. When the air/fuel mist enters the combustion chamber, engine heat helps vaporize the fuel. However, when the engine is cold the fuel does not vaporize as completely, so we must supply more fuel so that enough of it is vaporized for the engine to run. This is the purpose of the cold start mechanism (commonly called the choke) used on carbureted engines.
Carburetor Cold Start Mechanisms
There are currently two type of cold start mechanisms used in carburetors, the choke plate and the enrichener. The choke plate pivots to block off some of the incoming air, while the enrichener adds more fuel. Both methods result in the same condition, that is, a rich mixture in the neighborhood of 3:1. A fuel injection system does this by automatically increasing injector duration, which is how long the injector sprays fuel into the combustion chamber. The longer the injector duration, the more fuel is sprayed into the engine and the richer the mixture. Running a carbureted engine that is at or close to operating temperature with the cold start mechanism on will result in a rich mixture when it isn't needed and can result in fouled spark plugs.
Carburetors are mechanical/hydraulic/pneumatic devices that have several functions. They allow us to change engine speed by allowing more or less air/fuel mixture to enter the engine, they help atomize the fuel for better vaporization, and they provide varying air/fuel ratios under different throttle positions. For an engine at operating temperature, there are three basic fuel circuits.
Also known as the idle circuit or the slow speed circuit, it controls the air/fuel mixture while the engine is idling and up to about 1/8 throttle opening (it also flows fuel at larger throttle openings but the effect is negligible). Because of the small amount of fuel that is required at idle speeds, the pilot fuel passageway is restricted by the pilot jet. Carburetor jets (of any type) are usually made out of brass and come in different sizes. A number is stamped on the jet during manufacturing, the larger the number the larger the opening in the pilot jet and the richer the mixture would be. Because of the very small size of the opening in a pilot jet, is can easily be blocked by dirt, rust, stale fuel deposits or other debris. When this happens, the engine will not idle properly and the carburetor(s) will have to be removed, disassembled and cleaned.
As we open the throttle to accelerate, the carburetor allows more air to enter the engine, and there must be a corresponding increase in the amount of fuel flow. In most cases, this is accomplished by the use of a slide and jet needle, whether it is a mechanically operated slide or a vacuum operated slide. The jet needle raises and lowers with the slide and fits into a brass tube called the needle jet. Do not get confused between the two, the jet needle moves up and down while the needle jet is stationary in the body of the carburetor. The jet needle is tapered so that as it is raised in the needle jet, there is more space between the two and more fuel is allowed to flow. This circuit regulates the air/fuel mixture primarily from 1/8 throttle to about 3/4 throttle.
As the throttle is opened approaching full throttle, the carburetor allows even more air to enter the engine and the main jet now controls the amount of fuel that is supplied. As with the pilot jet, it is usually made of brass, comes in different sizes and has a number stamped on it. Again, the larger the number, the larger the opening and the more fuel is supplied for a richer mixture. Larger main jets are often required with changes to the intake and exhaust of the engine. The opening in a main jet is much larger than a pilot jet and is less likely to be blocked or restricted. This circuit regulates the air/fuel mixture primarily from 3/4 throttle to wide open throttle.
The 'Buffalo Theory' of Beer..
A herd of buffalo can move only as fast as the slowest buffalo.
When the herd is hunted,
it is the slowest and weakest ones at the back that are killed first.
This natural selection is good for the herd as a whole,
because the general speed and health of the whole group keeps improving by the regular killing of the weakest members.
In much the same way the human brain can only operate as fast as the slowest brain cells.
Excessive intake of alcohol, we all know, kills brain cells,
but naturally it attacks the slowest and weakest brain cells first.
In this way regular consumption of beer eliminates the weaker brain cells,
making the brain a faster and more efficient machine.
That's why you always feel smarter after a few beers, and that's why beer is so GOOD for you!
THINNING THE HERD" 2007 or "More proof of Darwin's theory"
Eighth Place: In Detroit, a 41-year-old man got stuck and drowned in two feet of water after squeezing head first through an 18-inch-wide sewer grate while trying to retrieve his car keys.
Seventh Place: A 49-year-old San Francisco stockbroker who often bragged he was "totally-zoned when he ran" accidentally jogged off a 100-foot high cliff on his daily workout.
Sixth Place: While at the beach, Daniel Jones, 21, dug an 8-foot hole for protection from the wind and had been sitting in a beach chair at the bottom when it collapsed, burying him beneath 5 feet of sand. People on the beach used their hands and shovels trying to get him out but could not reach him. It took rescue workers using heavy equipment almost an hour to free him. Jones was pronounced dead at a local hospital.
Fifth Place: Santiago Alvarado, 24, was killed as he fell through the ceiling of a bicycle shop he was burglarizing. Death was caused when the long flashlight he had placed in his mouth to keep his hands free rammed into the base of his skull as he hit the floor.
Fourth Place: Sylvester Briddell, Jr., 26, was killed as he won a bet with friends who said he would not put a revolver loaded with four cartridges into his mouth and pull the trigger.
Third Place: After stepping around a marked police patrol car parked at the front door, a man walked into H & J Leather & Firearms intent on robbing the store. The shop was full of customers and a uniformed officer was standing at the counter. Upon seeing the officer, the would-be robber announced a hold-up, and fired a few wild shots from a target pistol. The officer and a clerk promptly returned fire, and several customers also drew their guns and fired. The robber was pronounced dead at the scene by paramedics. Crime scene investigators located 47 expended cartridge cases in the shop. The subsequent autopsy revealed 23 gunshot wounds. Ballistics identified rounds from seven different weapons.
No one else was hurt.
HONORABLE MENTION: Paul Stiller, 47, and his wife Bonnie were bored just driving around at 2 A.M. so they lit a quarter stick of dynamite to toss out the window to create some excitement. Apparently they failed to notice the window was closed.
RUNNER UP: Kerry Bingham had been drinking with several friends when one of them said they knew a person who had bungee-jumped from a local bridge in the middle of traffic. The conversation grew more heated and at least 10 men trooped along the walkway of the bridge at 4:30 AM. Upon arrival at the midpoint of the bridge, they discovered that no one had brought a bungee rope. Bingham, who had continued drinking, volunteered and pointed out that a coil of lineman's cable lay nearby. They secured one end around Bingham's leg and tied the other to the bridge. His fall lasted 40 feet before the cable tightened and tore his foot off at the ankle. He miraculously survived his fall into the icy water and was rescued by two nearby fishermen. Bingham's foot was never located.
AND THE 2007 WINNER IS...
Zookeeper Friedrich Riesfeldt (Paderborn , Germany) fed his constipated elephant 22 doses of a animal laxative and more than a bushel of berries, figs and prunes, before the plugged-up pachyderm finally got relief. Investigators say ill-fated Friedrich, 46, was attempting to give the ailing elephant an olive oil enema when the beast suddenly unloaded. The sheer force of the elephant's unexpected defecation knocked Mr. Riesfeldt to the ground where he struck his head on a rock as the elephant continued to evacuate 200 pounds of dung on top of him, suffocating him. It seems to be just one of those freak accidents that once again proves..."S#@$ happens!"
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