2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 306Get this manual
FRONT ARMS AND FRONT SHOCK ABSORBER FRONT ARMS REMOVAL 1.Check: Front arm free play
Checking steps: Check the front arm side play by moving it from side to sideIf side play is noticeable, check the bushingsCheck the front arm vertical movement by moving it up and downIf the vertical movement is tight or rough, or if there is binding, check the bushings