Troubleshooting a Motorcycle Ignition System

Troubleshooting a Motorcycle Ignition System

a hot girl on a motorcycle surrounded by flame

Hi folks! I’ve noticed that lots of my readers, despite their interest in cossack motorcycles, own bikes of other brands. So I guess it’s high time for me to start writing something useful for the owners of other bikes as well. This will be my first article of general motorcycling type and it should be dedicated to one important aspect – a motorcycle ignition system.

As we all know, one of the most important things in motorcycles is the ignition system. It sparks the air-fuel mixture in cylinders and make the engine reveal its horsepower. The make the things easier to understand, let’s divide it into three elements – the ignition module, the coil and the wiring.

If you have carburetors on your engine, the module will require being properly adjusted for the engine to work as it should. I mean you need to set the right timing to ignite a spark discharge to spark the compressed combustion mixture. Determine the moment of ignition as the position of the engine crankshaft at the time the impulse is applied to the candle (spark plug) ahead of the upper dead center in degrees (typically from 1 degree to 30). This is due to the fact that it takes some time for the combustion of the working mixture in the cylinder (the speed of propagation of the flame front is about 20-30 m / s). If the mixture is ignited in the piston position at the top dead center (TDC), the mixture will burn already on the expansion stroke and partially on the outlet and will not provide effective pressure on the piston (simply speaking, catching the piston will fly out into the exhaust pipe). Therefore (the optimal) ignition timing is selected in this way (ahead of TDC) so that the maximum pressure of the burnt gases is at TDC. The optimum ignition timing depends on the speed of the piston (engine speed), the degree of enrichment/depletion of the mixture and slightly on the fractional composition of the fuel (affects the burning rate of the mixture).

If you have the EFI (electronic fuel injection) system, you won’t have to deal with setting the timing – the system will do this itself based on the current RPM and other parameters.

The impulse the ignition module produces is not enough to spark the compressed air-fuel mixture. That’s where the coil comes in. The ignition coil generates a high voltage of about 15,000 volts or even up to about 30,000 volts from the usual standard voltage of 12 volts. The incoming high voltage is distributed to the spark plugs. With this high voltage, the fuel-air mixture in the cylinder can be ignited.

The last but not the least part if the ignition system is the wiring and candles. All the wires should be solid.

Important: the wires going to the candle caps should have almost zero resistance.

As for candles, everything is quite simple here. Never equip your engine with bad spark plugs and try to replace them after a certain mileage, specific for every candle brand.

How to Find if Something Is Wrong

Here are the most common indicators of some ignition system malfunctions:

  • The motorcycle works roughly in the low-speed range.
  • The engine jerks or has power dips.
  • The engine heats up too fast or too much.
  • Increased fuel consumption.
  • Some start-up problems.

Please note that it’s not necessary the ignition system that causes these issues. Other parts of the motorcycle can lead to similar effects as well.

Whenever you find that something is wrong, it’s better to stop the bike and examine it. Even if the motorcycle with the defective ignition or some other engine part is still working, it is better not to continue riding, because this can cause more serious damage.

Dirt in the engine

If the engine is guaranteed to be in good order but is not working properly there is an urgent suspicion that there is dirt is in the gasoline or air flow. Checking your air filter for possible problems and draining the dirty gasoline and filling the gas tank with fresh fuel might help.

Important: never smoke near gasoline vapors. You will probably not like the consequences 🙂

What should we do if the problem occurs on the road?

If the mentioned symptoms occur on the road, you must check the ignition system. In case if there is a problem with the system you should reduce the acceleration speed and ride very slowly to the nearest motorcycle service or your garage to inspect the bike thoroughly. If all the parts of the system are easily accessible, like in case of my Dnipro MT, you can try finding and fixing the issue right on the road – check the ignition system for dry connections, faultless cabling and safe earth connection. Check if all candles produce good sparking. If some candle produces weak sparking, try replacing it with a new one, if you have it with you. If not, try changing the wiring with another candle to be sure that that problem is with the candle and not its cap or wire. The next thing to check is the coil – the best way is to replace it with another coil if you have one at hand. And the last step is to check the ignition module itself.

I’m sorry for not making the article more specific, but ignition systems vary from one motorcycle to another, so I mentioned only the steps that are common for most bikes.

Hope this info would be useful for someone.

Ride safe,


Alex White
Alex White
I'm just a guy who values 3 things in life: girls, bikes and freedom. I get them all with my custom-built Dnipro MT. Cossack motorcycles are truly unique and reliable bikes if being treated right, and I decided to create this blog and share my vast experience and love for cossack bikes with other bikers all over the world. Need my help or advice? Contact me via skype or email.

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