Kawasaki 400 throttle does not rebound.

Hello, I would like to ask why the Kawasaki 400 throttle doesn't rebound. Kawasaki 400 throttle does not rebound because:

1, the throttle pipe or throttle handle of Kawasaki 400 is stuck, and the throttle or throttle and oil needle of carburetor are stuck.

2. The throttle pipeline of Kawasaki 400 is not lubricated, the resistance is too great, or the route of the throttle pipeline is bent somewhere. Kawasaki Ninja 400 is an imitation motorcycle of Kawasaki Ninja series, with a displacement of 399cc. As a successor model of Ninja 300, it has undergone major upgrades in suspension and other parts.