Learn How To Remove Speed Limiter From Bike Safely

Are you asking, “Can I remove the speed limiter from my bike?” Yes, you can often remove or bypass the speed limiter on a motorcycle or scooter. This process, known as motorcycle derestriction, can give your bike more power and a higher top speed. However, it is very important to know the right ways to do this, the risks involved, and the laws in your area. This guide will help you grasp the workings of bike speed limiters and show you how to remove them safely and effectively.

How To Remove Speed Limiter From Bike
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Grasping Bike Speed Limiters

Many motorcycles and scooters, especially smaller ones, come with speed limiters. These limiters stop the bike from going faster than a certain speed. Makers put them there for different reasons.

Why Bikes Have Speed Limiters

Safety: For new riders or smaller engines, limiting speed helps prevent accidents.
Rules: Some countries have laws about how fast certain types of bikes, like mopeds or learner bikes, can go.
Insurance: Lower speeds might mean lower insurance costs.
Engine Life: Keeping the speed down can help the engine last longer.

These limiters can be set in different ways. Some are simple mechanical parts. Others are complex electronic systems. Knowing how they work is the first step to changing them.

Signs Your Bike Has a Limiter

It is not always easy to tell if your bike has a speed limiter. But some signs can point to one:

Sudden Power Loss: Your bike might pull strong but then suddenly feel like it loses power at a certain speed.
RPM Limit: The engine might hit a certain RPM (revolutions per minute) and not go any higher, even if you twist the throttle more.
Speed Rating: If your bike is a moped or a 50cc scooter, it almost certainly has a limiter to meet legal rules.
Known Models: Some bike models are known to have limiters from the factory. A quick search online for your bike’s model year can tell you.

What Happens When You Remove a Speed Limiter?

Removing a speed limiter means your bike can use its full power. This often leads to a top speed increase motorcycle owners look for. You also get better motorcycle acceleration improvement. Your bike will feel quicker off the line and have more pull through all gears. This can make riding more fun, especially on open roads.

However, removing the limiter also puts more stress on the engine and other parts. It also changes how the bike handles. This is why knowing how to do it safely is so important.

The Big Picture: Pros and Cons of Derestriction

Before you do anything, think about the good and bad sides of motorcycle derestriction.

Pros (Good Points):

More Speed: Your bike can go faster, reaching its true top speed.
Better Power: You will feel more power and torque. This helps when going up hills or passing other vehicles.
Quicker Starts: Your bike will pick up speed much faster. This is part of the motorcycle acceleration improvement.
Full Potential: You unlock all the power the maker built into the engine.

Cons (Bad Points):

Safety Risks: A faster bike needs more skill to ride. It also takes longer to stop.
Legal Trouble: The legality of derestricting bike varies. In many places, it is against the law, especially for mopeds or learner bikes. You could get fined or lose your license.
Insurance Problems: Your insurance might not cover you if you crash a derestricted bike. Some policies become void if you change the bike.
Warranty Void: If your bike is new, derestricting it will almost certainly void your warranty. The maker will not fix problems for free.
Bike Wear: More speed and power mean more stress on the engine, brakes, tires, and suspension. Parts might wear out faster.
Higher Costs: You might need to upgrade other parts, like brakes or tires, to handle the extra speed safely. Fuel use might also go up.

You must think about these points carefully. For many, the added risk is not worth the extra speed.

How Speed Limiters Work and How to Change Them

Speed limiters work in different ways. Some stop the engine from making full power. Others limit the fuel flow or spark timing. Knowing the type of limiter your bike has helps you choose the right method for bike power restriction removal.

1. CDI Restrictor Removal

What it is: The CDI (Capacitor Discharge Ignition) unit controls the bike’s spark timing. A restricted CDI unit might limit the engine’s RPMs. This is a common way to limit speed on smaller bikes and scooters.

How it works: A restricted CDI unit sends fewer sparks or changes when they happen. This stops the engine from reaching high RPMs, which limits the top speed.

How to change it:
* Replace the CDI: The simplest way is to swap the restricted CDI for an unrestricted one. These are often sold as “performance” or “racing” CDIs.
* Cut a Wire: On some older or simpler bikes, a wire on the CDI unit might be the limiter. Cutting or grounding this wire removes the limit. But be careful; cutting the wrong wire can damage the CDI or engine. It is best to check a service manual for your specific bike.

Steps for CDI removal (General Idea):
1. Find the CDI: It is often a small box, usually near the battery or under the seat. It will have several wires plugged into it.
2. Unplug the old CDI: Carefully unplug the wire harness from the old CDI.
3. Plug in the new CDI: Connect the wire harness to the new, unrestricted CDI unit.
4. Test: Start the bike and take it for a slow ride to see if the limit is gone.

Tool List:
- Screwdriver (Phillips or flathead, depending on fasteners)
- Wrench set (if you need to remove bolts to get to the CDI)
- Wire cutters/strippers (if cutting wires)
- New unrestricted CDI unit

2. Scooter Speed Limiter Bypass (Variator Washers/Rollers)

What it is: Many scooters use a CVT (Continuously Variable Transmission) system. This system uses weights called rollers and a variator to change gear ratios. A simple washer or a set of heavy rollers can limit the scooter’s top speed. This is a common moped performance upgrades method.

How it works: A small washer placed in the variator stops the belt from going out to its full range. This keeps the gear ratio lower, which limits the top speed. Heavier rollers also affect acceleration and top speed.

How to change it:
* Remove the Variator Washer: This is often the easiest way to remove a mechanical limiter on a scooter. You open the transmission case, take apart the variator, and remove the washer.
* Change Variator Rollers: Changing to lighter rollers can give better acceleration. Heavier rollers can give a higher top speed, but might make acceleration slower. Finding the right roller weight is key for balanced performance.

Steps for Variator Washer Removal (General Idea):
1. Take off the CVT Cover: You will need to remove several bolts to get the transmission cover off.
2. Hold the Variator: You might need a special tool to hold the variator still.
3. Remove the Nut: Undo the large nut holding the variator in place.
4. Take out the Variator: Slide the outer variator plate, belt, and then the variator body off the shaft.
5. Find the Washer: Look for a thin metal washer behind the variator body, sitting on the shaft. Remove it.
6. Put it Back Together: Reassemble everything carefully. Make sure the belt is seated right.

Tool List:
- Wrench set (for CVT cover bolts and variator nut)
- Impact wrench (can make removing the variator nut easier)
- Variator holding tool (highly recommended)
- Gloves
- New variator rollers (optional, for tuning)

3. Bike ECU Reflash / Electronic Speed Governor Defeat

What it is: Modern bikes use an ECU (Engine Control Unit), which is like the bike’s brain. It controls fuel, spark, and many other engine functions. An electronic speed governor defeat is a program inside the ECU that limits speed. This is common on larger, fuel-injected bikes. This method also allows for significant bike power restriction removal and top speed increase motorcycle.

How it works: The ECU is programmed to cut fuel or spark when the bike reaches a certain speed. This stops the engine from making more power at that speed.

How to change it:
* ECU Reflash/Remap: This involves changing the software inside the ECU. You can send your ECU to a specialist, or use a tool to do it yourself if you know how. This is the most complex method. A good reflash can also improve fuel use and power delivery across the whole RPM range.
* Add-on Modules (e.g., Power Commander): These devices plug into your bike’s wiring harness. They change the signals from the ECU to the engine, letting you fine-tune fuel delivery and ignition timing. They don’t remove the limiter directly, but they can bypass it or add more power. This is part of many moped performance upgrades.

Steps for ECU Reflash (General Idea – for Professionals):
1. Connect to ECU: A special cable connects a computer to the bike’s diagnostic port or directly to the ECU.
2. Read Original Map: The software reads the current settings from the ECU.
3. Modify Map: The tuner changes the speed limit settings, fuel maps, ignition timing, and other parameters.
4. Write New Map: The new, derestricted map is written back to the ECU.
5. Test: The bike is tested on a dyno (a machine that measures power) to ensure everything works well.

Tool List (for self-reflash, not recommended for beginners):
- Specialized ECU flashing tool/software
- Laptop
- Dyno (for proper tuning)
- Recommendation: This job is best left to professional tuners. Trying it yourself without proper knowledge can permanently damage your ECU or engine.

4. Exhaust and Intake Restrictions

What it is: Some bikes have restrictors in the exhaust system (like a small pipe or a baffle) or in the air intake (like a smaller air filter opening). These parts limit how much air and fuel can get into or out of the engine.

How it works: A restricted exhaust system makes it harder for engine gases to leave, which lowers power. A restricted intake means less air gets in, also lowering power.

How to change it:
* Remove Exhaust Baffle/Catalytic Converter: Some exhaust systems have removable baffles that quiet the bike and restrict flow. Removing them can add power. A catalytic converter also restricts flow.
* Replace Exhaust System: Installing a full aftermarket exhaust system designed for performance will greatly improve airflow and power.
* Open up Intake: This might mean changing the air filter to a less restrictive one or removing any blockages in the airbox.

Tool List:
- Wrench set (for exhaust bolts)
- Screwdriver (for airbox)
- New exhaust system (optional)
- New air filter (optional)

Legality of Derestricting Your Bike

The legality of derestricting bike is a very important topic. It changes a lot from one country to another, and even from one state or province to another.

Mopeds and Learner Bikes: For small bikes like mopeds (often limited to 28 mph or 45 km/h) or bikes used by new riders, derestricting is almost always against the law. These bikes are sold with speed limits to meet specific license rules. If you remove the limiter, your bike is no longer legal for that license class. You could get caught without the right license, which can lead to big fines, points on your license, or even your bike being taken away.
Insurance: If you have an accident on a derestricted bike that is supposed to be restricted, your insurance company might not pay for damages. This could leave you with huge bills.
Emissions: Changing the engine setup can also make your bike produce more pollution. This might make it illegal to ride in areas with strict emissions rules.
Roadworthiness: A bike that goes faster needs better brakes and tires. If you change the speed but not these parts, your bike might not be safe to ride on the road.

Always check your local laws before you do any work on your bike’s speed limiter. In many places, keeping your bike legally compliant means leaving the limiter in place.

Safety First: Key Things to Think About

Removing a speed limiter makes your bike faster. This means you must think about safety even more.

Rider Skill and Experience

Can You Handle It? A bike with more power and speed needs more skill to ride. If you are a new rider, a derestricted bike can be very dangerous. Practice on roads you know well. Learn to handle the bike at higher speeds.
Advanced Training: Think about taking an advanced riding course. These courses teach you how to handle a bike better at speed and in hard situations.

Bike Condition and Upgrades

Brakes: Can your brakes handle the extra speed? You might need better brake pads or even bigger brake discs.
Tires: Your tires must be in good shape and rated for higher speeds. Worn or low-quality tires will not give you the grip you need.
Suspension: The suspension needs to handle higher speeds and harder braking. If it is old or worn, you might need to fix or upgrade it.
Frame: Is your bike’s frame strong enough for the extra stress of higher speeds? Most factory frames are, but it is worth a thought for very old bikes.
Maintenance: A derestricted bike needs more frequent checks and servicing. Parts will wear out faster. Keep up with your bike’s maintenance schedule.

Road Conditions

Where Will You Ride? Fast bikes are not for city streets with lots of traffic. They are best for open roads or tracks. Always ride within your limits and the road conditions.

Steps for Derestricting Your Bike (General Advice)

This section gives a general overview. Always look up specific guides for your bike model.

Find Out Your Bike’s Limiter Type:
- Look at your bike’s service manual.
- Search online forums for your specific model.
- Ask experienced mechanics.
- Often, 50cc scooters have variator washers and restricted CDIs. Larger, newer bikes might have ECU limiters.
Get the Right Parts and Tools:
- For CDI: A new, unrestricted CDI unit.
- For Variator: Variator holding tool, impact wrench (or strong hand tools), new rollers (optional).
- For ECU: This is almost always a job for a professional.
- For Exhaust/Intake: New performance exhaust or air filter, tools to remove old parts.
Follow a Step-by-Step Guide for Your Bike:
- Do not guess. Find a detailed guide or video for your exact bike model.
- Take your time. Do not rush any steps.
- Take photos as you go to help you put things back together.
Test Safely:
- After removing the limiter, ride the bike slowly at first.
- Find a safe, open area (like a private road or track) to test the new top speed and acceleration.
- Listen for any strange noises. Check for leaks.
- Make sure your brakes still work well.
Consider Professional Help:
- If you are not sure about any step, or if you do not have the right tools, take your bike to a professional mechanic. They have the knowledge and tools to do the job right and safely. This is especially true for bike ECU reflash jobs.

After Derestriction: Tuning and Upgrades

Removing a limiter is often just the first step for many riders. For the best performance and engine health, you might need more tuning and upgrades.

Tuning the Engine

Fueling: When you change the air intake or exhaust, the engine might run too lean or too rich. You might need to change the fuel map or the carburetor jets. This is very important for engine life. An electronic speed governor defeat often includes fuel map changes.
Spark Timing: For bikes with ECUs, a professional tune can also adjust spark timing for more power.
Dyno Tuning: The best way to tune a derestricted bike is on a dyno. This machine measures power and fuel use at different RPMs. A tuner can adjust your bike’s settings on the dyno for peak performance and safety.

Other Performance Upgrades

Sprockets: Changing the front or rear sprockets can change your gear ratios. A smaller front sprocket or a larger rear sprocket gives more acceleration but lower top speed. The opposite gives more top speed but slower acceleration. This is a simple moped performance upgrades option.
Performance Air Filter: A less restrictive air filter can let more air into the engine, adding power.
Performance Exhaust: A full exhaust system can free up many horses, especially when paired with an ECU reflash. This supports bike power restriction removal.
Lighter Parts: Lighter wheels or other parts can make the bike quicker to accelerate and handle better.

A Table of Common Restrictors and Methods

Restrictor Type	How It Works	Common Bikes Affected	Removal/Bypass Method	Complexity Level
CDI Unit	Limits engine RPM (revolutions per minute)	50cc scooters, small motorcycles	Replace with unrestricted CDI; Cut wire	Easy to Medium
Variator Washer	Stops CVT belt from reaching full range	Most scooters (50cc-150cc)	Remove the washer from variator	Easy
ECU/Speed Governor	Electronic limit in engine’s computer	Modern, fuel-injected motorcycles	ECU reflash/remap; Add-on module (e.g., Power Commander)	High
Exhaust/Intake Restrictors	Limits airflow into/out of engine	Various bikes and scooters	Remove baffles; Replace exhaust/air filter	Medium
Carburetor Jets	Controls fuel-air mix; some bikes have smaller jets	Older carbureted bikes/scooters	Replace with larger jets	Medium
Throttle Stop Screw	Physically limits how far throttle can open	Some learner/off-road bikes	Adjust or remove screw	Easy

Interpreting Risks and Responsibilities

When you derestrict a bike, you take on more risks and responsibilities.

Your Responsibility: You are responsible for your own safety and the safety of others on the road. A faster bike needs more careful riding.
Legal Consequences: If you break the law by riding a derestricted bike, you will face the consequences. This might include fines, license points, or even jail time in severe cases.
Bike Longevity: Pushing an engine beyond its factory limits can make it wear out faster. Be prepared for more maintenance and possible repairs.
Environmental Impact: Removing emissions controls or improperly tuning the engine can lead to more pollution.

Think about these points before you change your bike. For many people, a stock bike is more than enough for daily riding and fun.

Frequently Asked Questions (FAQ)

Q1: Is it safe to remove a speed limiter from my bike?
A1: Removing a speed limiter makes your bike faster and more powerful. This can make it less safe if you are not an experienced rider or if your bike’s other parts (brakes, tires, suspension) are not upgraded to match the extra speed. It also adds more stress to the engine.

Q2: Will derestricting my bike make it faster?
A2: Yes, motorcycle derestriction aims to give you a top speed increase motorcycle owners often want, along with better motorcycle acceleration improvement. Your bike will be able to reach its full potential power.

Q3: Is it illegal to derestrict a bike?
A3: The legality of derestricting bike varies greatly by region. For mopeds or bikes designed for learners, it is almost always illegal and can lead to serious penalties, including voided insurance. Always check local laws.

Q4: Will removing the speed limiter void my bike’s warranty?
A4: Yes, almost certainly. If your bike is under warranty, making any unauthorized changes, like removing a speed limiter, will usually void the warranty. The bike maker will not cover repairs.

Q5: What is a CDI restrictor removal?
A5: A CDI restrictor removal involves replacing or modifying the CDI (Capacitor Discharge Ignition) unit. This unit controls the engine’s spark, and a restricted CDI limits the engine’s RPMs, thus limiting speed. Removing the restrictor allows the engine to rev higher.

Q6: What is a bike ECU reflash?
A6: A bike ECU reflash involves changing the software program inside the bike’s Engine Control Unit (ECU). The ECU acts as the bike’s brain, controlling fuel and spark. Reflashing can remove electronic speed governors, change fuel maps, and adjust timing for more power and a higher top speed. This is part of electronic speed governor defeat.

Q7: Can I derestrict my scooter?
A7: Yes, scooter speed limiter bypass methods are common. These often involve removing a variator washer, changing the CDI unit, or adjusting the carburetor. These are common moped performance upgrades.

Q8: Do I need to upgrade other parts after derestricting my bike?
A8: It is highly recommended. For safety, you should think about upgrading your brakes, tires, and possibly suspension to handle the increased speed and power. Without these upgrades, the bike might not be safe to ride.

Q9: Will derestricting use more fuel?
A9: Yes, a derestricted bike will generally use more fuel. More power means more fuel is burned. Also, if the engine is not properly tuned after derestriction, it can be even less fuel-efficient.

Q10: What is bike power restriction removal?
A10: Bike power restriction removal is the general term for any action taken to unlock the full power of a bike’s engine that was limited by the manufacturer. This includes removing speed limiters, changing exhaust, and remapping the ECU for more power.

Q11: How long does it take to derestrict a bike?
A11: It depends on the method. Removing a variator washer might take an hour or two. Swapping a CDI can be very quick. An ECU reflash or full engine tune by a professional can take several hours, including dyno time.

Q12: Should I do it myself or go to a mechanic?
A12: Simple tasks like variator washer removal or CDI swaps can often be done by a careful person with the right tools. But for complex jobs like ECU reflashing or carburetor tuning, it is much safer and better to go to a professional mechanic or tuner. They have the right equipment and knowledge to do the job safely and correctly.