Why can't the motorcycle exceed 60 km/h?
3 Answers
The reasons why a motorcycle cannot exceed 60 km/h are as follows: Low fuel: A lean air-fuel mixture causes insufficient piston thrust after ignition combustion, prolongs combustion time, and leads to engine overheating. The symptoms of a lean mixture include poor acceleration during operation, temporary improvement when manually adjusting the choke or pumping fuel, and recurring weak acceleration without enriching the mixture - indicating a fuel-deficient state. Rich fuel: An overly rich air-fuel mixture causes weak acceleration at low speeds. The lack of sufficient oxygen during combustion of a rich mixture results in incomplete combustion, reduced power output, decreased fuel efficiency, and excessive carbon buildup that clogs exhaust components, worsening the weak acceleration. Clogged air filter or high carburetor float level: This can cause carburetor float chamber overflow; loose carburetor main jet; poor enrichment system reset; or blocked carburetor main air jet. Poor fuel quality or incorrect gasoline octane rating: May cause engine knocking; expired gasoline decomposes and loses calorific value; water in fuel causes intermittent engine operation and backfiring; presence of other contaminants in gasoline.
I've been repairing motorcycles for 20 years, and this kind of issue is very common. It could be that the chain is too loose and slipping, preventing power from reaching the wheel, or the clutch plates are worn, making acceleration difficult. Check if the spark plug is dirty; the ignition system needs to be normal for proper combustion. Poor fuel quality or a clogged fuel tank vent can also slow you down, especially noticeable when climbing hills. Long-term lack of maintenance can lead to carbon buildup in the engine, lowering the compression ratio—it's recommended to clean the throttle body regularly. Also, insufficient tire pressure increases rolling resistance. For safety, don't force it; find a repair shop to check with a diagnostic computer, as DIY attempts can easily go wrong.
I've been riding motorcycles for five years, and the most annoying thing is when the speed won't go up. Last time my bike was stuck at 60 because the carburetor was too dirty and clogged. I fixed it by taking it apart and spraying it with cleaner, saving hundreds of dollars. Improper chain tension and old, high-viscosity engine oil also affect acceleration. A poorly tuned aftermarket exhaust can actually hinder performance, as the stock setup is more stable. Regularly changing the engine oil and keeping the air filter clean ensures smooth airflow and better power. If the bike feels sluggish at high speeds, shut it off and check to avoid small issues becoming big problems.
