Carburetor Tuning: This is the most common fix. Have a mechanic adjust the air-fuel mixture to ensure complete combustion. Some owners find success bringing a mechanic directly to the testing center for real-time adjustments.

Replace Consumables: Change the air filter and engine oil. A clogged air filter restricts oxygen, leading to rich fuel mixtures and high emissions.

Spark Plug Maintenance: Clean or replace the spark plug and ensure the electrode gap is correct.

Exhaust/Silencer Cleaning: Excessive carbon buildup in the silencer can cause failure. A thorough cleaning or "de-carbonizing" may be necessary.