What Causes a Motorcycle to Have Unstable Firing with a 'Tututu' Sound?

[VanDallas]

When a motorcycle only makes a 'tututu' sound but fails to start during ignition, there are several potential causes to consider. It is necessary to separately check whether the spark plug is faulty, whether there is a misfire or the high voltage is too weak, whether the gasoline is of poor quality, whether the carburetor is clogged (clean the carburetor), and whether the carburetor's air-fuel mixture ratio is improperly adjusted. Additionally, check whether the choke is used incorrectly or has issues preventing the enrichment of the mixture, whether the valve clearance is too small or the valves are not sealing properly, whether there is a flooded cylinder, whether the cylinder pressure is too low, whether there is slight air leakage in the intake pipe or other rubber hoses, and whether the valve timing is incorrect. Any of these issues could lead to this type of malfunction.