2003 Suzuki LT-Z400 Factory Service Manual, Page 272Get this manual
SERVICING INFORMATION
Complaint Transmission jumps out of gear
Symptom and possible causes 1Worn gear2Worn or distorted gearshift fork3Weakened gearshift stopper spring4Worn gearshift pawl1Tappet clearance out of adjustment2Improper valve seating3Worn valve guide4Worn camshaft5Excessive spark plug gap6Defective ignition coil7Defective generator8Defective COl unit9Incorrect float chamber fuel level10Clogged carburetor jet1Weak valve spring2Worn camshaft3Insufficient spark plug gap4Mistimed valves5Ignition not advanced sufficiently due to poorly working timing advance circuit6Defective ignition coil7Defective generator8Defective COl unit9Low float chamber fuel level10Dirty air cleaner element11Clogged fuel hose, resulting in inadequate fuel supply to carburetor1Excessive amount of engine oil2Worn cylinder3Worn piston ring4Worn valve guide5Scored or scuffed cylinder wall6Worn valve stem7Defective valve stem oil seal8Worn oil ring side rail1Insufficient tappet clearance2Weak valve spring3Mistimed valves4Worn cylinder5Worn piston ring6Improper valve seating7Fouled spark plug8Incorrect spark plug9Clogged carburetor jet10Incorrect float chamber fuel level11Dirty air cleaner element12Air leakage from intake pipe13Excessive amount of engine oilReplaceReplaceReplaceReplace