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What Is Motorcycle Choke & Its Purpose?

Last updated on 04-Jul-2022 , By Saleh

Many of you surely have experienced the difficulties of starting a cold engine or bike early in the morning. In such case most of the bikers are very well known about the part of the bike which helps to make the cold engine starting job easy in the morning and that is motorcycle choke. So today we are herewith motorcycle choke & its purpose (Source).

What Is Motorcycle Choke & Its Purpose?


What is Motorcycle Choke?

First making the term clear the choke is the essential part of the carburetor fitted bikes. In carburetor fitted bikes the air-fuel mixture composed and feed the engine mechanically or somewhat manually.

And in such mechanical technology motorcycle carburetor choke presence is mandatory. It plays its roll to make instant rich air-fuel mixture to deal with environmental and temperature issues.

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Motorcycle choke is nothing but a pulling lever attached with the carburetor. It may have attached directly with carburetor or may have set on handle bar or on front panel but connected with the carburetor with a cable. Wherever the lever has set it directly operates a valve of carburetor and the full assembly called as choke.


What is the Motorcycle Choke Purpose or Roll?

In early days it was somewhat essential pulling the choke lever out for starting a cold engine. It was quite necessary pulling the choke in the morning to start a cold engine. In summer I may not need so frequently but in winter sometimes it needed pulling the lever every time when starting.

Therefore whatever the time or weather it needed to start a cold engine the question is, what is the reason or what is the purpose of choke? And what the roll it plays on starting a cold engine?

Yes choke lever directly increases the fuel ratio in air-fuel mixture.  In carburetor chock lever operates a valve or gate to control air or fuel to rich the fuel in the mixture.

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The chock lever mechanism works to increase fuel or decrease the air ratio in the supply. Thus the chock instantly riches the air-fuel mixture and helps to quick ignition in cold engine. So that is the purpose or roll of a chock lever.


Motorcycle Choke – How It Works?

In carburetor, choke lever riches the air-fuel mixture and helps for cold starting in morning or while starting for first in a day or after a long-unused period. But here the question is how the choke works?

In carburetor the air-fuel mixture ratio is fixed but can be tuned. It works in a mechanical sequence operated by the throttle. But here there is no automatic mechanism to change the ratio according to weather or other relative conditions.

So in such situation when cold engine or weather requires for higher or rich ratio of air-fuel mixture than carburetor choke does it mechanically. The basic technology we also mentioned earlier as it increases fuel supply or decreases the airflow.


In the old model carburetors choke operates a smaller gate or butterfly wing against the throttle butterfly gate or valve. It makes a barrier to the airflow gate to reduce airflow but the fuel flow stays constant. So the fuel ratio increases in terms of lower flow of air.

But in new model carburetors the main flow of air and fuel stay constant according to throttle. So when the choke lever pulled, there a valve opened in the main air intake hole. The whole directly goes through the carburetor fuel reserve bucket.


Therefore when the choke lever pulled the valve opens its lid and air inhaled through this lid. It directly sucks the fuel from bucket due to piston vacuum pressure or venture effect. It feeds this excess fuel to the regular air-fuel mixture flow before the engine intake manifold.

Therefore in both model of carburetor the fuel ratio increases in the mixture and makes it rich. And this works for fast and quick ignition in cold engine and weather situation. Thus the choke works increasing the fuel ratio.

Does it harm engine pulling the choke every time?

We many time faces the frequent question on choke that is does it harms frequent choking? The answer is NO. Starting the cold engine or in cold weather or in other situation is not harmful. It’s a necessary job.

But using the choke unnecessarily is just wastage of fuel. As it increases fuel in mixture to richen the ratio so fuel consumed more than the normal situation. Other than it using choke in cold engine is good.

It also helps to lubricate the cylinder upper wall when it is dry when starting in the first time in the morning. Thus it also protects the wearing.


Does EFI have Choke?

In EFI engine the manual choke lever mechanism is absent. Here the air-fuel mixture automatically controlled and changed by the ECU considering weather, temperature and other situation. It automatically controls both air and fuel injections. And it also has own mechanism to rich the mixture.

In EFI engine ECU does rich mixture automatically. It does with its pre-programming and according to its sensor readings of various considering parameters.

It directly sprays extra fuel to increase fuel ratio in needed situation with its dedicated fuel spray nozzle. So EFI engine doesn’t have manual choke lever but have mechanism of auto choking.

So readers here were all about our discussion on motorcycle choke & its purpose. Wish you got the clearer idea about motorcycle choke and its activity.

Therefore if you have more to know or have any specific query please let us know. We will surely try to respond at our convenient time. Thank you all.

 FAQ- Frequently Ask Question

1. What is the purpose of a choke on a motorbike?

Ans: When the engine is cold, the engine likes more petrol in the mixture than usual. The choke normally "chokes" the air supply into the engine so it gets more petrol than general.

2. Is it bad to ride a motorcycle with the choke on?

Ans:  The choke only operates when the throttle is totally closed, so as soon as you crack the throttle to ride off, the choke is not affecting the fuel mixture

3. Is the choke should be open or closed?

Ans:The choke is only used when starting a cold engine. When we doing a cold start, the choke suppose to be closed to limit the amount of air going in.   

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Published by Saleh

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