There are a number of reasons why your bike jumps and surges and jumps with steady throttle when you apply the gas pedal. These reasons can range from simple to complicated.
The most likely reason is that your ignition system is not delivering enough spark to the cylinders. Basically your engine is starving for fuel, not bad gas but no gas at all. This can be caused by a number of things including weak or broken battery cables, clogged fuel filter, clogged fuel injectors, dirty or worn out spark plugs or distributor cap and rotor, bad ignition coil(s), or because you don’t have enough voltage coming from the stator.
Also, your 2-stroke will surge and jump when it runs out of fuel. It’s like running out of gas in a 4 stroke, but the 2 stroke can’t sense that it’s running out of fuel properly and instead of shutting off it keeps running. If your bike does this with a steady throttle you’ve probably got a vacuum leak – either near the carb or at the exhaust port.
Why is my bike surging/stumbling at cruising speeds?
This can be a result of either an ignition timing issue or the Advance Fuel Injection (AFI) feature which allows additional fuel to be added to the engine as needed. The simplest way to identify which it is is if the stalling occurs at highway speeds, then you likely have an issue with timing. If it stalls mainly in low speed traffic, or when riding slowly around town, then this may indicate an issue with AFI.
Why did my motorcycle lose Power When Accelerating?
A motorcycle’s power is limited by the torque produced by the motor and this torque is transferred through a transmission to the rear wheel using a chain or a belt drive. If any of these components begin to fail, you will lose either power or control of your motorcycle. This can lead to an accident and injury. Often times, people riding motorcycles will accelerate quickly in order to catch up to traffic or be able to pass another vehicle.
If your motorcycle has lost power when accelerating, it’s time to check the carburetor. A carburetor is a device that controls the flow of air and fuel in a liquid-fueled internal combustion engine such as those found on motorcycles and automobiles.
What Causes Motorcycle Engine Idle Rpms To Vary?
There are usually two reasons why motorcycle idle rpm changes. The first reason is the throttle stop screw. Some motorcycles have a screw on the right side that allows you to adjust how much air goes into the carburetor when the throttle is opened. This can affect how much fuel gets delivered to the engine, so it causes idle rpm changes. Another common cause of idle rpm changes is due to a worn carburetor main jet. This part delivers fuel to the engine, and if it is worn out, then it will not meter out as much fuel while idling, which will cause idle rpm changes.
What causes Stumbling/Surging while riding at 1/4 throttle?
The Stuttering/Surging problem is caused by a number of factors: Air filter restriction, Spark plug fouling from improper break-in or fuel contamination, Insufficient fuel delivery due to worn injector tips, Leaking valves or valve guides, Air leak in the intake tract, Exhaust restriction causing incorrect pulse timing at the cylinder.
At low speeds, a motorcycle engine runs in the “lean” mode for maximum efficiency. This means that there’s not enough fuel mixed with air to completely burn the mixture and release the correct amount of power. Some of this unburned mixture creeps into the exhaust and eventually gets burned by a catalytic converter located near one of your mufflers.
Why does my bike surging/jerking at steady throttle?
The surging/jerking of a bike at steady throttle is a sign that the engine is not staying in effective operation range. When this happens it is best to increase the amount of throttle but always keeping the rpms within the bikes range.
If your bike is surging or jerking idling at steady throttle, it could be either a carburetor float level or mixture problem. Carburetor float levels should be checked regularly, making sure to top off the fuel level with fresh gasoline if necessary. If the float clearance is set correctly but the bike still runs poorly, check that the air filter is clean and free of debris and replace if necessary.
The next step is to adjust the fuel/air mix based on altitude and temperature. Check for vacuum leaks by running your hand along all hoses and connections, and check for unplugged wires by checking that each spark plug wire has a bright pink band around its terminal.
Another reason for surging or jerking at steady throttle is that the engine is out of tune. The ECU has a vast array of sensors and controls, with which it monitors all aspects of engine performance, including air flow, coolant temperature, and fuel mixture.
If the ECU detects any issue with the way your bike is running it will compensate by adjusting ignition timing accordingly to either retard or advance it. If this correction is not drastic enough then it will send an additional signal to the fuel injectors telling them to increase or decrease their flow rate in order to lean out or richen the air/fuel mixture until it detects that there are no longer issues and then resumes idle speed operation.
If you have ever performed diagnostic tests on any electronic device then this process might sound familiar as many computers do exactly the same thing when they encounter an error condition.
Why is my bike Bucking at constant throttle?
A bucking is created when you are accelerating from a stop and getting into the throttle in a very quick manner. This makes the motor go to full throttle and the sudden burst of power overcomes the natural pull generated by your bike’s suspension , causing immense oscillation. This can be easily fixed by adjusting your suspension, changing forks, making sure everything on your bike is tight and secure, or changing/installing a stiffer spring in your rear shock .
Bucking has a number of possible causes. The most commonly overlooked cause of bucking is the throttle position sensor (TPS). It may be dirty, corroded or shorted out in part, or not working properly. It’s possible that the TPS can become intermittent due to dirt and moisture getting down into it or oxidization on the terminals making intermittent contact.
Why does my bike stall when throttling?
When you stall your bike and can’t get it to start, the first thing to check is your throttle cables. A little bit of play in these cables might cause the throttle to stick or bind, which could make you stall. Start by removing the side cover on your carburetor and visually inspecting both ends of each cable. You should be able to see any fraying or damage.
If there is any visible damage, replace that cable with a new one of equal length. If there isn’t any visible issues, try lightly lubricating both ends of each cable where they enter the carburetor body with a touch of engine oil and see if that makes your throttle feel better.
What Causes Motorcycle Engine Idle Rpms To Vary?
Engine idle speed and rpm speeds vary from individual bike to individual bike based on a number of factors. The engine size, weight and even the rider’s height can each contribute to an engine’s normal idle speed.
The variations in the idle rpm of a motorcycle are mainly regulated by three factors.
The first one is found in the air flow through the carburetor and its impact on engine temperature, which in turn causes the rpm to vary.
The second one is related to the change of engine load during acceleration as well as deceleration.
Finally, any kind of changes in atmospheric pressure can also affect the idle speed of your engine.
Why is my bike experiencing surging at low rpm/throttle opening?
A surging bike at low rpm/throttle opening is a common problem many riders experience, and in most cases it’s simply because the pilot is unaware of how to properly operate the throttle. It’s very important to understand that how you operate the throttle has a great impact on how your bike will respond. The most common mistake riders make is simply opening up the throttle all at once when they want to accelerate, which results in a surge or VTEC hesitation in most cases.
This is because when you open up the throttle completely it causes an over abundance of air/fuel mixture entering into your motor, which can be overwhelming if not properly tuned. The more immediate way for someone to experience this type of problem would be to just crack open their throttle and dump gas into their motor without even attempting any form of acceleration.
When jetting is lean, why does the engine surge?
Lean jetting is the most common cause of surging. This is because lean mixtures tend to oscillate, or surge, rather than combust and burn evenly across an entire engine’s speed range. By adjusting the needle clip position, you can control how much fuel enters the vacuum circuit or main fuel bowl, which will vary from aircraft to aircraft. The more fuel that enters before it reaches the manifold, the richer the mixture will be; whereas less fuel will yield a leaner mixture.
When the engine is running lean, the mixture is too lean and more fuel is needed to keep it running smoothly. The excess fuel (unneeded) will cause the engine to surge. This happens because too much extra fuel is being added.
Take a deep breath and think about where you are going. When you are running a lean fuel mixture, your engine will run hotter than normal. The hotter it is, the more air it needs to burn a given amount of fuel. So it surges for the same reason that you feel short of breath when you run around the track: You are not getting enough oxygen.
Do I have the dreaded “Surging”?
The old-fashioned way to check for surging is to time the time it takes to fill a glass with water. Starting with an empty glass, set the stopwatch and start pouring. When you get close to the top of the glass, time how long it took to fill and then subtract that amount from 60 seconds. If the amount is more than 15 seconds, you probably have surging.
Why do I experience surging at a specific throttle setting
You may be experiencing surging at a specific throttle setting. This can happen when your engine intakes air with too much/too little air pressure to the carburetor. To address this problem, you’ll want to check for correct carburetor jetting, first and foremost. If you find issues with jetting, then adjust as necessary. Additionally, if the idle speed is set too high, this can cause the engine to shudder and surge on the low end of its throttle range.
The engine will surge in acceleration if the throttle blades are not fully opened. The following is a description of the causes for this condition.
1. Insufficient air flow into the air cleaner due to dirty air filter or clogged mass airflow sensor (MAF) element.
2. Throttle cable is incorrectly adjusted and/or binding at any point from lever to carburetor throttle butterfly.
3. Carburetor jetting incorrect (lean).
4. Engine vacuum leak between throttle plates and engine cylinder head caused by warped valve seals or piston rings, improper head gasket installation or blockage at PCV valve, crankcase vent line or oil fill cap mesh screen.
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Why does my bike surges and jumps with steady throttle? – Summary.
In summary to our topic of discussion Why does my bike surges and jumps with steady throttle? The answer given was and still remains that the most likely reason is that your ignition system is not delivering enough spark to the cylinders. Basically your engine is starving for fuel, not bad gas but no gas at all. This can be caused by a number of things including weak or broken battery cables, clogged fuel filter, clogged fuel injectors, dirty or worn out spark plugs or distributor cap and rotor, bad ignition coil(s), or because you don’t have enough voltage coming from the stator.