What happened to the broken rocker arm of motorcycle?

Screw quality problem, rocker shaft is too tight.

1, screw quality problem, when the rocker arm rotates at high speed, the screw in the rocker arm is stressed too much, which leads to the fracture of the rocker arm.

2. The rocker shaft is too tight. Because the rocker arm shaft is too tight, it can't rotate when the rocker arm needs high-speed rotation, which leads to the fracture of the rocker arm.