Yes, bad spark plugs can potentially cause blue smoke to be emitted from a motorcycle's exhaust. Blue smoke is often an indication of burning oil, and there are a few ways in which faulty spark plugs can contribute to this issue:
Incomplete Combustion: When spark plugs are worn out or fouled, they may not provide a strong enough spark to ignite the air-fuel mixture properly. This incomplete combustion can lead to unburned fuel and oil passing through the exhaust system, resulting in blue smoke.
Oil Fouling: If the spark plugs are covered in oil deposits, it can be a sign of oil leakage into the combustion chamber. This oil can accumulate on the spark plug electrodes, causing them to malfunction and leading to poor combustion and the production of blue smoke.
Malfunctioning Ignition System: Faulty spark plugs can disrupt the overall functioning of the ignition system, affecting the timing and intensity of the spark. This can lead to irregular combustion and an increased likelihood of oil burning and blue smoke emission.
It's important to note that while bad spark plugs can contribute to blue smoke, there can be other underlying causes as well. Issues such as worn piston rings, valve seals, or cylinder head gasket leaks can also result in oil entering the combustion chamber and causing blue smoke. If you notice persistent blue smoke from your motorcycle's exhaust, it's advisable to have it inspected by a qualified mechanic who can diagnose the exact cause and recommend the necessary repairs.