What is the purpose of Chokes are in bikes?

Question

I have seen chokes used in motor cycles and bikes if there the starting problem then we are asked to pull the choke and start and release it back to the position. can you explain why is needed and how it function.

Answer 1

The function of the choke is to regulate the air/fuel mixture during engine startup. It produces a higher concentration of fuel (a "richer" fuel/air mixture) when the engine is cold, then gradually increases the concentration of air (making the fuel mixture "leaner") as the engine warms up. This is accomplished by a butterfly valve in the throat of the carburetor, at the very top. When this valve is closed the flow of air is very much reduced and the fuel/air mixture is "rich." When the valve is open (i.e., the butterfly is standing straight up), the flow of air is maximized and the fuel/air mixture is "lean."

Answer 2

First, lets get things straight. Some of the guys who have answered gave a good answer for lawn mowers and very small scooters, etc, but not motorcycles. Most carburatred bikes have a by-pass choking system, which is in reality a miniture carb in built into the side of the main carb. With the butterfly or slide closed, this miniture carb is turned on by the choke lever or knob, which pulls a plunger out, and clears the hole, which goes from the air inlet of the carb, to the body, between the butterfly/slide and engine. There is a tube which drops in to the fuel in the float bowl, this tube has a restriction, to form a jet, to control the flow of fuel on choke. This tube is blocked, when choke is closed. So, for the choke to work, the throttle must be closed, choke on, and start the engine. When started, give a bit more throttle, and as it warms up, slowly push the choke off (closed). This type choke has only been used for the past 40 years or so, on most all Japanese made machines, and a few others. Of course, the old English bikes had the Tickler on the Amal carbs, which allowed you to fill the carb float bowl, before kick starting. Harleys, unless you have an S&S Carb, and the mini stuff are the only bikes with the chokes you guys describe.

Tomcotexas

Answer 3

Chokes serve a very important purpose when it comes to cold starting a bike or a car. The choke simply cuts of the carburettor's air supply, thus making the air fuel mixture very rich. When the engine is cold, the cold fuel vaporizes slowly and so there is the need for a rich air fuel mixture. The choke creates a vacuum or a low pressure area in the throat of the carburettor in order to pull in the extra fuel. You are asked to put it back into its position because the rich air fuel mixture should gradually be leaned off.

Answer 4

Used to cut back on the air-fuel mixture so that the fuel will ignite in the chamber when the engine is cold. Once it warms up it needs more air in the mixture so you cut back on the choke.

Answer 5

first off its not a choke its an enrichiner, a choke is what you do to people that you dont like. your enrichiner is only to be opened for as minimum of a time as posible. what it dose is give you a higher air feul mixtuer wich alows your mc to start when its not warmed up. not depending on the type carb you have and the type jet you have in your carb will depand on when you need to use it. the reason you dont want to leave it open for to long is it will foul your pluggs.

Answer 6

Cold start - chokes is closed (less air, more fuel)
Run motor - chokes open (more air, less fuel)

Answer 7

usually used for cold starts. it basically gives the bike a little more gas flow it get it started.

Answer 8

so that some petrol can burn easily to start the engine