Yamaha YFM400FAR Service Manual

Also see for YFM400FAR: Owner's manual Service manual Assembly manual

Contents

7 - 1DRIVTROUBLESHOOTINGDRIVE TRAINTROUBLESHOOTINGThe following conditions may indicate damaged shaft drive components:NOTE:Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite subtle anddifficult to distinguish from normal machine operating noise. If there is reason to believe thesecomponents are damaged, remove the components and check them.Symptoms Possible Causes1.A pronounced hesitation or “jerky” movementduring acceleration, deceleration, or sustainedspeed. (This must not be confused withengine surging or transmissioncharacteristics.)2.A “rolling rumble” noticeable at low speed; ahigh-pitched whine; a “clunk” from a shaftdrive component or area.3.A locked-up condition of the shaft drive trainmechanism, no power transmitted from theengine to the front and/or rear wheel.A.Bearing damage.B. Improper gear lash.C.Gear tooth damage.D. Broken drive shaft.E.Broken gear teeth.F. Seizure due to lack of lubrication.G.Small foreign objects lodged between themoving parts.1.Check: Unusual noises*****************************************************The following “noises” may indicate amechanical defect:a.A “rolling rumble” noise during coasting,acceleration, or deceleration. The noiseincreases with front and/or rear wheel speed,but it does not increase with higher engine ortransmission speeds.Diagnosis: Possible wheel bearing damage.b.A “whining” noise that varies withacceleration and deceleration.Diagnosis: Possible incorrect reassembly,too-little gear lash.