What is the diameter of a motorcycle valve stem?

[AnnieRose]

Motorcycle valve stems typically have a diameter of 5mm, but the size may vary depending on the valve stem model. Introduction to valve stems: The valve stem is cylindrical and continuously performs reciprocating motion within the valve guide. Its surface must undergo heat treatment and polishing. The shape of the valve stem end depends on the fixing method of the valve spring. The commonly used structure involves two half-lock pieces to secure the spring seat, with the valve stem end having a groove for installing the lock pieces. Some use a lock pin for fixing, with a hole at the end for installing the lock pin. Common faults and causes of motorcycle valve stems: Common faults of motorcycle valve stems include bending or breakage. The main causes include non-standard clearance between the valve and valve guide, quality issues with the guide or valve, and weakened tension of the valve spring.