What are the reasons for a motorcycle not running fast?

[Riley]

The reasons for a motorcycle not running fast are as follows: 1. Exhaust pipe blockage: Specific reasons: The exhaust pipe is blocked by carbon deposits and dirt, or the front bent section of the exhaust pipe is dented from impact. Such motorcycles perform fine at low speeds but cannot reach high speeds. Repair method: Remove the exhaust pipe and use a drain cleaning spring or a hand drill with a steel wire rope to scrape off the internal carbon deposits, or burn off the carbon deposits with high-temperature flames. 2. Air filter blockage: Specific reasons: The rubber pipe is bent and blocks airflow, the foam plastic inside the air filter is clogged with dust, or severe fuel enrichment caused by blocked air intake. Repair method: Adjust the intake pipe and clean the foam plastic inside the air filter. If the air filter is normal, adjust the carburetor to prevent severe fuel enrichment.