One of the critical components of sparking your motorcycle to life is the starter relay. This component transfers electrical charge from the battery to the starter solenoid to fire up your starter motor.
While starter relay problems aren’t necessarily widespread, all mechanical parts wear out, eventually.
Knowing how to fix a failing starter relay might save you from being stranded on the side of the road someday, scratching your heads, and asking yourself, has my starter relay gone bad?
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Here’s the Short Answer to Know When Your Motorcycle Starter Relay Gone Bad:
If your motorcycle’s starter relay has gone bad, you could experience your starter clicking while you’re trying to start the bike, while in some cases, the bike might be cold dead, with no sounds at all. Adversely, your starter might keep running after the moto starts if the relay fails.
How to Tell When a Motorcycle Starter Relay Has Gone Bad
You can tell if your starter relay is bad if your motorcycle has problems starting, whether no crank at all, a clicking, or it starts, but the starter motor keeps running.
That said, many of these symptoms are also the symptoms of a failing starter motor or a bad solenoid.
Let’s cut to the troubleshooting process and break down the symptoms of a bad starter relay and look at the specifics.
1. Motorcycle Won’t Start
The number one sign a starter relay is done for is that nothing happens when you’re trying to start your motorcycle—no click, no crank, no ticking; nada.
- Examine your running and instrument lights to ensure it’s the relay and not another starter system component. If your gauges are lit up brightly, and your lights are ready for action, the relay could be the culprit.
- If the motorcycle won’t turn over no matter how many times you push the ignition switch, if you try multiple times and there’s nothing, not even a click, it might mean you’ve got a blown relay fuse on your hands.
- If, after a few turns, your starter clicks, or maybe your bike even fires up, it might be that your relay is dying but not quite dead yet. Regardless, a starter system diagnosis would be the next step in determining if it is, in fact, your relay that’s causing the problem.
2. Starter Continues to Crank After Bike Fires Up
We’ve mentioned another symptom of a failing starter relay a few times if the starter continues to crank after the bike starts and runs.
How the starter relay process works on a healthy bike:
- When you push your starter button, your battery sends current through the relay and the starter solenoid.
- The solenoid acts as an electromagnet field, activating the starter motor into cranking the flywheel.
- Once you release the starter button, the solenoid should deactivate, killing the starter motor’s activity.
- However, if your relay fails, the starter relay continues to charge the solenoid; the starter motor keeps firing in attempts to start the bike after it is already running.
This could result from the relay being in contact with a component generating or charged with electrical power—the electricity keeps the relay’s current live after the starter switch is released.
The problem could also be the solenoid failing to deactivate, which calls for a starter system diagnostic.
Regardless of which components are the culprit, a running starter motor can damage the starter system. Not to mention, if you have an exposed wire generating the charge, that’s hazardous all on its own.
3. Starter Clicks Rapidly, But Bike Never Ignites
If you hear your relay letting off a rapid-fire of clicks, but the bike never cranks over, chances are the starter motor isn’t getting the juice it needs from the relay to start your bike’s engine.
If your motorcycle’s starter relay clicks but fails to pass the current to the starter motor:
- either your relay is too weak, worn, or damaged to surge the solenoid,
- or the battery isn’t charged enough to activate the relay beyond a couple of clicks.
- whether it’s your relay or your battery that’s not up to the task of activating the solenoid, it needs to be replaced right away;
- low power start-ups can damage your starter system more severely.
The cause of a clicking relay coil is corrosion on the relay itself, either from wear, harsh weather exposure, or old age.
If a corroded relay is your issue, clean the contact points following your moto-manufacturers service manual guidelines to restore proper contact and increase current flow. Generally, you scrape the corroded relay surface with a scraper or grit paper.
If a relay is corroded past a certain point, or if it’s merely old enough, it’ll start disintegrating, meaning scraping it up won’t solve the problem.
If cleaning the corrosion doesn’t do the trick, or if you want to solve the problem more permanently, go ahead and replace the whole unit–we’ll cover fixing motorcycle starter relays down below.
4. Motorcycle has Intermittent Starting Problems
If your bike has inconsistent starting patterns–if there’s a secret trick to start your motorcycle like pushing the starter button over and over again until the bike starts–you might have a bad starter relay.
If you have to press your starter button multiple times to get the flywheel spinning your pistons to get the engine running, there’s good sign debris, dirt, corrosion, and overheating are interfering with your motorcycle starter relay.
Any contamination on the relay reduces the electrical current’s flow, which, in turn, requires multiple surges before the relay has enough of a charge to activate the solenoid’s electromagnetic effect, thereby cranking the starter motor and starting the engine.
What Causes the Starter Relay to Go Bad?
Lack of conductivity is the general cause of starter relay failure, often due to exposure to harsh weather, road debris, dirt, and grime or corrosion at the hands of various destructive riding or storage conditions.
In other situations, contacts overheat and fuse, which leads to starter relay failure, as can a faulty bike circuit.
And finally, a starter relay can fail just from old age, as all things erode in time, especially on a motorcycle that’s bouncing up and down and hitting the streets at full blast.
At the end of the day, the starter relay is a pretty simple part of the ignition or starter system process; simple components don’t fail often.
How Do You Isolate a Bad Starter Relay on a Motorcycle?
Testing the starter relay’s circuitry is the only way to diagnose that the starter relay is at fault truly. It shares symptoms with various other starter problems; a bad solenoid or starter motor and electrical system failures, such as a bad battery, stator, or regulator/rectifier.
Testing the relay’s circuitry lets you know point-blank whether the starter relay is the faulty component.
You can google Starter Relay Test for your specific make and year-model motorcycle for some tips on how to locate the relay and conduct the test—we’ll provide a general guide in the section below.
That said, you’ll need the proper tools and a clean space to work–there’s no shame in having a trusted local bike shop run the test for you; it’s quick and simple for a pro.
How Do You Test a Starter Relay on a Motorcycle?
As we mentioned above, the starter relay is the component in your starter system that relays power from the battery to the starter motor. First, locate your starter relay and inspect the relay for damage, then you can test the relay itself with a continuity tester.
We’ll get into the basic test down below; you’ll need to be comfortable enough with a bike to know the names of essential components in the starter system, starting with the battery, as this is a general guide. Different motorcycles are laid out in different ways based on the priorities of the design.
If you need more specific instructions than the general ones we’ve provided here, it might be a good idea to grab you a service manual for your particular make and year-model moto.
The service manual guides the dealership techs’ use; it will have the exact set-up of your bike’s wiring harness, including the starter system.
Remember, if you don’t have the tools or space needed to conduct the following procedures or if you can’t find access to a service manual and you’re unsure about your working knowledge, any decent bike tech can do this test on the fly for pretty cheap.
- Step 1: Locate the starter relay and examine your starter relay’s 30 amp fuse for any indication of corrosion. Swap out the fuse if it’s looking rough.
- Step 2: Attach the black jumper wire from the negative battery terminal to the green or red wire of the starter relay.
- Step 3: Fasten the red jumper wire from the positive battery post to the starter relay’s yellow or red wire terminal. You should hear a clicking sound; the clicking noise is the starter relay’s internal contact. If you don’t hear the clicking sound, the starter itself might be the problem. Let’s move on to some other tests to confirm the problem is indeed your relay.
- Step 4: Detach the red jumper wire from the starter relay as soon as you finish with the third step.
- Step 5: Hook your Continuity Tester’s wires up to your starter relay’s battery terminal and starter motor terminal. Read the labels to tell which is which. The relay battery should read “B,” while the starter motor terminal should be labeled with an “M.” Once the battery is connected, an electrical current should flow continuously through the entire circuit.
- Step 6: Monitor the gauge needle on the Continuity Tester to read if your flow is continuous. Note: If there was no clicking noise during Step 3 and there’s no continuity during step 6, you’ve got a faulty relay, and there is no continuity when the battery is connected, the starter relay in your motorcycle is busted.
Can You Fix a Motorcycle Starter Relay?
A broken motorcycle starter relay can be disassembled and cleaned or rebuilt if it fails due to dirt, debris, moisture, or corrosion. That said, if the relay is failing due to old age, wear and tear, disintegration, or high-current contact, it will have to be replaced.
Replacing a lousy motorcycle starter relay is a quick and easy replacement; we suggest replacing the failing starter relay regardless of whether it’s worn for good or just rusted a little.
Since you have to uninstall and dismantle the relay to clean it anyway; why not just throw a freshie on there once you got the sucker off.
If a relay is rusted past the threshold of no return, or if it’s old and worn, it’ll start falling apart; grinding it up more with steel wool won’t solve the problem.
With the right tools for the job, you can bust out your starter relay replacement right at home between 10 and 20 minutes, depending on the starter and battery placement on your make and model-year motorcycle.
You can find model-specific installation instructions online or in the service manual for your specific make and year-model motorcycle.