Motorcycle spark plugs - types, symptoms and replacement
Machine operation

Motorcycle spark plugs - types, symptoms and replacement

The spark plug is mounted on the cylinder head. Due to the high voltage currents that are generated in the ignition coil, the spark plug creates a discharge capable of igniting the air-fuel mixture in the combustion chamber. The explosion causes the piston to move, which is then transmitted through the connecting rod to the crankshaft and on to the transmission. The motorcycle will not start without a spark plug.

Types of motorcycle spark plugs

Candles can be divided by calorific value:

  • Od 2 to 6 V. These spark plugs are suitable if the engine is not subjected to heavy loads. Ideal for motorcycles that are mainly used in winter and for short trips.

  • Od 7 to 11 V. These candles are able to withstand heavy loads. Ideal for motorcycles that are used mainly in summer, for long trips and for fast riding.

Pay attention to the material from which the candle is made. Candles can be:

  • nickel. The cheapest, they are enough for 15 - 000 km.

  • copper. They are popular among drivers due to attractive prices. Their service life is 20 - 000 km.

  • Iridium. They are durable and work well under any load. They are enough for about 60 - 000 km.

  • Platinum. They are able to withstand the effects of electrical discharges. They are enough for about 60 - 000 km.

  • Gilding. The most expensive type, mainly installed on racing bikes. Their service life is as much as 80 - 000 km.

What are the best candles?

The best candles are those that follow the manufacturer's recommendations and instructions. The right spark plug has a positive effect on combustion, exhaust emissions, engine power and proper engine operation, so be sure to check your motorcycle's service book before buying.

Symptoms and causes of failed spark plugs

The most natural cause is operational wear. This causes problems when starting the engine when it is cold and damp outside. The driver may also notice increased fuel consumption. Another reason failure of valve sealswhich can cause oil flooding. This causes starting problems and uneven engine operation. Too little insulator leads to the formation of deposits on the electrodes. It also leads to starting problems and uneven engine operation. Also look out for these signs of wear:

  • uneven idling,

  • jerks when driving and starting,

  • Difficulty starting the engine (especially in a cold state),

  • Excessive muffler smoke, black or gray smoke.

If you are in doubt about the condition of the spark plugs, you can remove them and inspect them. A good spark plug has a white or white-yellow insulator. There is also no carbon deposits, deposits, greasy deposits and other contaminants around the electrodes. ATTENTION! As soon as you unscrew the candle, you can not screw it back. It may come to deformation of the sealing washerwhich should press the candle in the nest; the candle will also poor thread sealwhich means it will dissipate heat better. Screwing in the same candle a second time increases it risk of blown spark plugwhich can lead to damage and costly failure of the engine head.

How to change spark plugs on a motorcycle step by step

Before carrying out any work, remember that the ignition MUST be turned off and the spark plugs can only be removed when the engine is COLD. You will avoid burns and blocked candles. Also remember that spark plugs have been replaced.

It is also recommended that you refer to your motorcycle's service book/manual, if you have one. It contains information on the easiest way to get to the spark plugs. Depending on the motorcycle model, it may be necessary to remove the fairing, radiator, or other parts. 

  1. Remove the nozzles or unscrew the fasteners of the coil pipes. Pay attention to which spark plug is serviced by which cap, as a mistake can result in damage or starting problems. Find a wiring diagram, take a photo or mark the wires with tape.

  2. Clean the candle from various contaminants. Compressed air helps a lot.

  3. Remove the candle. Make sure it was removed along with the washer.

  4. Remove any debris around the spark plug mounting hole.

  5. Screw in a new spark plug. Start by hand to make sure the spark plug is fully seated in the threads. Tighten the spark plug by hand until tight.

  6. Set the torque wrench to the correct torque, slide the wrench onto the socket and tighten to the correct torque.

  7. After installing the candles, we put on the pipes and turn the motorcycle.

Attention!

Be careful to screw in the spark plug correctly. If you overtighten the spark plug, it can overheat and damage the engine, spark plug, and threads. Insufficient tightening is also harmful - we are talking about overheating, loss of compression, thread damage and damage / breakage of the insulator.

The above information comes from:

https://moto.autodoc.pl/czesci/motocykl-zwieca-zaplonowa-43192

Instructions for changing spark plugs are taken from:

DIY: how to change spark plugs on a motorcycle yourself?

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