1997 Yamaha YFM600FWAK ATV Service Manual, Page 201Get this manual
TROUBLESHOOTING
IDRIVI-te
Too-little gear lash is extremely destructive to the gear teethIf test ride following reassembly indicates this condition, stop riding immediately to minimize gear damage
c.A slight "thunk" evident at low speed operationThis noise must be distinguished from normal machine operationDiagnosis: Possible broken gear teeth
A WARNING
Stop riding immediately if broken gear teeth are suspectedThis condition could result in the shaft drive assembly lockingup, causing loss of control of the machine and possible injury to the rider