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Is your motorcycle dying when the choke is off? This problem occurs when a carbureted motorcycle sits over the years or is not serviced for too long.
In this guide, we’ll learn what causes a motorcycle or ATV that only runs on a choke and the engine dies when the choke is off. I’ll teach you how to fix this issue on any carbureted motorcycle step-by-step.
Table of Contents
- 1 Why Does My Bike Engine Stop When I Turn Off The Choke?
- 2 Understanding The Working Of Choke In Carbureted Internal Combustion Engines
- 3 How To Fix A Motorcycle Dies When Choke Is Off
- 4 Can I Ride My Motorcycle With Choke On?
- 5 Conclusion
Why Does My Bike Engine Stop When I Turn Off The Choke?
If your motorcycle dies when the choke is off, it’s a classic symptom that your engine is running on a lean air-fuel mixture. A partially or fully clogged pilot jet is causing this issue. To fix this, you must clean your carburetor pilot jet to enrich the air-fuel ratio.
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Understanding The Working Of Choke In Carbureted Internal Combustion Engines
Before knowing why your motorcycle engine shuts when the choke is off, it’s essential to understand what a choke is, why it is used, and how it works.
I have explained everything in detail.
A choke is a valve/cable that restricts airflow before the carburetor to increase the proportion of fuel in the air-fuel mixture.
It is used to make the air-fuel mixture rich during cold start. The rich air-fuel mixture supply makes the engine cranking easy in low-temperature conditions.
How To Fix A Motorcycle Dies When Choke Is Off
Your motorcycle only runs on the choke, which means the carburetor supplies a lean air-fuel mixture to the combustion chamber. Faults in the fuel supply line mainly cause it.
Here is how to troubleshoot the problem:
1. Clean Your Carburetor
If your motorcycle has been sitting for over six months or has not been serviced for a long, most probably the dirt has clogged the fuel jets.
So, start your troubleshooting by cleaning the carburetor.
- Firstly, turn off your petcock to prevent gas flow and remove the carburetor by unscrewing the necessary bolts.
- Now, unscrew the bolts around the side of the bowl to disassemble the carburetor. Remember that some gas is already in the bowl, so don’t forget to open it on a towel.
- Next, remove the float pin and keep it carefully. After that, unscrew the fuel jets (main jet and pilot jet) and try to look through them.
- If jets are clogged, strip a copper electrical wire, unclog the jet, and spray the carburetor cleaner several times.
- After cleaning the jets, use carb cleaner spray to clean other carburetor parts, such as the throttle body, spray nozzle, float chamber, fuel bowl, etc.
- Now, assemble everything back to your motorcycle, and your problem will be fixed. Don’t forget to turn on the petcock and wait a few minutes until the carb bowl is filled with fuel.
2. Clean Your Fuel Line
If your fuel line is plugged with dust or gunk, it won’t supply enough fuel to run the engine. In this case, the motorcycle starts on the choke and dies when the choke is off.
You need to unclog the fuel line with compressed air to solve this problem. If it doesn’t clean, replace the fuel pipe.
3. Fix Air Leakage
Any air leakage to the inlet valve makes the air-fuel mixture lean, which results in poor engine performance and power output.
You should ensure that the clamp holding the air intake boot to the carburetor is tight and that the clamp mounting the intake boot to the cylinder is also tight.
Another easy way to find out air leakage is smoke. Make a white smoke by burning a paper roll or cigarette and see where it is being sucked. You may need to replace the hose if it’s leaking.
Can I Ride My Motorcycle With Choke On?
If a choke is set to the ON position, it restricts the air intake to the carburetor, making the air-fuel mixture too rich.
A rich air-fuel mixture is required during a cold start and won’t hurt your engine for a shorter period.
However, running your motorcycle with the choke on long distances may foul the spark plug, cylinder wall wear, and increase fuel consumption.
So, riding a motorcycle with a choke on will hurt the engine in the long term. It’s only used to crank the engine when the outside temperature is low.
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In 90% of cases, a motorcycle dies when the choke is off because of a clogged pilot jet. Cleaning the carburetor and adjusting the screw fixes the problem. You must clean and tune your carburetor every six months for smoother rides.
Follow the above-mentioned solutions and let me know in the comment box if your problem is fixed!