GN 125 Indicator Flash Rate Explained

It's a common quandary for Suzuki GN 125 owners, and indeed many motorcycle riders: how fast should those indicators be flashing? You've noticed your GN 125's indicators are blinking rather enthusiastically, perhaps around 150 times a minute, and a friend has warned you about potential MOT failure if it's over 120 flashes per minute. This is a perfectly valid concern, and understanding the regulations and the underlying mechanics can save you a trip back to the testing station. Let's delve into the world of motorcycle indicators, specifically for the beloved GN 125, and shed some light on this flashing predicament.

Understanding Indicator Flash Rates: The Legalities

The primary concern here is compliance with MOT (Ministry of Transport) testing standards in the UK. While specific regulations can be updated, the general principle for vehicle direction indicators is that they should flash at a steady rate, and critically, not too fast. The commonly cited figure of 120 flashes per minute is indeed a widely accepted benchmark for the maximum permissible flash rate for indicators on all vehicles, including motorcycles. This rate translates to approximately 2 flashes per second. Any rate significantly exceeding this can be interpreted as a fault, potentially leading to an MOT failure.

Why the strict limit? A flash rate that is too fast can be visually confusing for other road users. It can make it difficult to discern whether the indicator is functioning correctly or if the vehicle is actually turning. A consistent, steady flash at a moderate pace is crucial for clear communication on the road. A rapid, almost frantic flashing could be mistaken for an electrical fault or simply be too distracting.

Why Might Your GN 125 Indicators Be Flashing Too Fast?

Several factors can contribute to an excessively fast indicator flash rate on a Suzuki GN 125, or indeed any motorcycle. The most common culprit is related to the flasher relay. The flasher relay is an electro-mechanical or solid-state device that interrupts the flow of current to the indicators, causing them to flash. It does this by using a bimetallic strip that heats up and bends, breaking the circuit, or through electronic components in newer relays.

The speed at which the flasher relay operates is directly influenced by the electrical load applied to it. This load is determined by the power consumption of the indicator bulbs.:

• Bulb Wattage: The standard GN 125 typically uses a specific wattage for its indicator bulbs. If one or more of these bulbs has been replaced with a lower wattage bulb (e.g., a 10W bulb instead of a 21W bulb, although this is less common for indicators), the electrical load on the flasher relay is reduced. With less load, the relay operates faster, resulting in a quicker flash rate.
• Faulty Flasher Relay: Over time, flasher relays can degrade. An older or faulty relay might not be regulating the flash rate correctly, even with the correct bulb wattage.
• Wiring Issues: While less common, a short circuit or a resistance issue in the indicator wiring could also potentially affect the load and, consequently, the flash rate. However, this is more likely to cause the indicators to not work at all or behave erratically in other ways.

The Easiest Way to Slow Down Your Indicators

Given that the most frequent cause of fast flashing is a reduced electrical load, the simplest and most effective solution is to restore the correct load to the flasher relay. Here are the most common methods:

1. Ensuring Correct Bulb Wattage

The first and most straightforward step is to verify that you have the correct wattage indicator bulbs installed. For most GN 125 models, the standard indicator bulbs are 10-watt bulbs. If you've recently replaced a bulb and suspect it might be the wrong wattage, or if you've installed aftermarket "clear" or "smoked" lenses which sometimes come with different bulb recommendations, this is the place to start.

Action: Remove one of your indicator bulbs and check the wattage printed on the glass or the base. If it's not 10 watts (or whatever the specified wattage for your specific GN 125 model is), replace it with the correct one. You can usually purchase these from motorcycle parts suppliers or even reputable auto accessory shops.

2. Installing Resistors

If you are committed to using lower wattage bulbs (for aesthetic reasons, perhaps) or if you've installed LED indicators, which have a significantly lower power draw than traditional filament bulbs, you will need to compensate for the reduced load. This is where resistors come in.

Flasher relays are designed to work within a specific resistance range. When you switch to LEDs or lower wattage bulbs, you effectively lower the resistance, causing the relay to cycle faster. By adding a load resistor in parallel with each LED indicator (or lower wattage bulb), you increase the overall resistance and bring it back into the range the flasher relay expects, thus slowing down the flash rate.

How to install resistors:

1. Purchase the correct resistors: You'll need resistors that can handle the wattage of your indicator bulbs and are designed for automotive use. Typically, 10-watt or 25-watt ceramic resistors are used. The resistance value (measured in ohms, denoted by 'Ω') needs to be calculated based on the original bulb wattage and the new LED wattage. A common recommendation for converting traditional incandescent indicators to LEDs is to use a resistor of around 150Ω to 300Ω. It's often best to buy a "resistor kit" specifically for motorcycle LED indicators, as these will come with the correct values and sometimes even pre-attached connectors.
2. Locate the indicator wiring: You'll need to identify the positive (+) and negative (-) wires going to each indicator. This usually involves accessing the wiring loom near the indicator unit itself.
3. Wire in the resistors: The resistor needs to be wired in parallel with the indicator bulb. This means connecting one end of the resistor to the positive wire feeding the indicator, and the other end of the resistor to the negative wire. You can do this by splicing into the existing wires and using crimp connectors, or by using "T-tap" connectors for a less invasive connection. Ensure all connections are secure and insulated with heat shrink tubing or electrical tape.

Important Note on Resistors: Resistors generate heat when current flows through them. Ensure you mount them in a location where they won't melt plastic or come into contact with flammable materials. Securing them to a metal frame part is often a good idea. You will typically need one resistor per indicator if you are converting to LEDs.

3. Replacing the Flasher Relay

If ensuring correct bulb wattage doesn't solve the problem, or if you've decided to upgrade to LED indicators and want a cleaner solution than adding resistors, you can replace the original flasher relay with an electronic flasher relay or an adjustable flasher relay.

• Electronic Flasher Relays: These relays are solid-state and are not dependent on the electrical load of the bulbs. They will flash at a consistent rate regardless of whether you are using incandescent bulbs or LEDs. You simply need to purchase an electronic flasher relay that is compatible with your motorcycle's electrical system (often a 3-pin or 2-pin unit) and swap it out with the original.
• Adjustable Flasher Relays: These are a fantastic option if you want precise control over your flash rate. They usually have a small dial or screw that allows you to adjust the flashing speed. This is ideal if you want to fine-tune the rate to a specific speed, perhaps slightly faster or slower than the standard, but still within legal limits.

How to replace the flasher relay:

1. Locate the original flasher relay: On the GN 125, the flasher relay is typically a small, often rectangular or cylindrical unit, usually mounted near the fuse box or under the seat. It will have wires connected to it, usually with labels indicating the function (e.g., 'L' for load/output, 'B' for battery/input, 'E' for earth/ground).
2. Disconnect the old relay: Carefully unplug the original relay. Make a note of which wires go into which terminals.
3. Connect the new relay: Connect the new electronic or adjustable flasher relay according to its wiring diagram. Ensure the connections are secure. If you are switching to a 3-pin electronic relay from a 2-pin original, you may need to bridge a connection or ensure the earth wire is properly connected.

Table: Solutions for Fast Indicator Flashing

Here's a quick comparison of the methods:

Frequently Asked Questions (FAQs)

Q1: What is the exact legal flash rate for motorcycle indicators in the UK?

A1: The generally accepted legal maximum flash rate for vehicle indicators in the UK is 120 flashes per minute (approximately 2 flashes per second). The rate should also be steady and consistent.

Q2: Can I use LED indicators on my GN 125?

A2: Yes, you can use LED indicators on your GN 125. However, because LEDs draw much less power than standard incandescent bulbs, you will almost certainly need to either install load resistors or replace the original flasher relay with an electronic or adjustable one to prevent them from flashing too fast and to ensure they are visible and compliant.

Q3: Do I need a resistor for each indicator?

A3: Typically, yes. If you are converting to LEDs, you will need to install a resistor for each indicator bulb to ensure each circuit has the correct load. Some kits might offer dual-resistors, but it's more common to wire one resistor per indicator.

Q4: Where can I buy flasher relays or resistors for my GN 125?

A4: You can find these parts at most motorcycle accessory shops, online motorcycle parts retailers (such as Oxford Products, Pyramid Plastics, or specialist Suzuki parts suppliers), and general automotive parts stores. Ensure the part is compatible with your GN 125 model.

Q5: Will my indicators flash fast if only one bulb is out?

A5: Yes, this is a common behaviour. When an indicator bulb burns out, the electrical load on the flasher relay is significantly reduced, causing the remaining bulb(s) to flash much faster. This rapid flashing is often a built-in indicator that a bulb has failed.

Conclusion

The rapid flashing of your Suzuki GN 125's indicators is a common issue, often stemming from a reduced electrical load on the flasher relay. By ensuring you have the correct wattage bulbs, or by employing solutions like load resistors or a new flasher relay, you can easily rectify this problem. Not only will this help you pass your MOT, but it also ensures your indicators are communicating your intentions clearly and safely to other road users. Don't let a fast flash rate leave you in the dark or facing an unnecessary re-test; take action and keep your GN 125 roadworthy and safe.