White smoke from the exhaust and a frequent decrease in engine oil level in a Honda Unicorn motorcycle can indicate a potential issue. Here are a few possible causes and solutions:
Worn Piston Rings: If the piston rings are worn or damaged, it can allow oil to pass into the combustion chamber, resulting in white smoke. The oil consumption will also increase. The solution is to replace the piston rings, which may require engine disassembly.
Cylinder Head Gasket Leakage: A faulty cylinder head gasket can cause oil to leak into the combustion chamber, resulting in white smoke. Inspect the gasket for signs of damage or leakage and replace it if necessary.
Valve Stem Seal Leakage: If the valve stem seals are worn or damaged, they can allow oil to enter the combustion chamber. This can lead to white smoke during startup or acceleration. Replace the faulty valve stem seals to resolve the issue.
Overfilled Engine Oil: Excess oil in the engine can cause it to burn and produce white smoke. Check the engine oil level and ensure it is within the recommended range. If it is overfilled, drain the excess oil to the proper level.
Incorrect Fuel Mixture: A too-rich fuel mixture can result in white smoke. Make sure the carburetor or fuel injection system is properly adjusted to maintain the correct air-fuel ratio.
If the issue persists or you are unsure about the cause, it is recommended to take your Honda Unicorn to a certified mechanic or Honda service center for a thorough inspection and proper diagnosis. They will be able to identify the specific problem and provide an appropriate solution.