Troubleshooting Guide - Yamaha RD125C Servicehandbuch

C H A P T E R 7. A P P E N D I C E S
7-1. Troubleshooting guide
The following guide is not complete in itself. If a problem is found within an
individual component mentioned within the chart, refer to the section or chapter
involved for inspection procedures.
A . No Start or difficult to Start
Possible Cause
Remedy
Ignition System
No spark
1 Check ignition main switch.
2. Check ignition kill switch.
3. Check point assembly.
4. Check condenser.
5. Check wiring.
6. Check coil.
7. Check high tension lead.
8. Check spark plug.
Weak or intermittent spark
1. Use Electro-Tester, spark gap test.
2. Check spark plug.
3. Check high tension lead.
4. Check ignition coil and points.
Air/Fuel Systems
No fuel 1. Check fuel tank.
2. Check fuel petcock.
3. Remove main jet, check fuel flow.
Intermittent or poor fuel flow
1. Clean fuel tank, check fuel tank
cap vent.
2. Clean fuel petcock.
3. Remove carburetor, service.
Bad fuel
1. Flush fuel System, completely.
2. A d d fresh fuel. proper grade.
Blocked air intake or malfunction 1. Clean and lube filter.
2. Check reed valve assembly.
Possible Cause
Remedy
Engine/Exhaust Systems
Incorrect compression pressure
1. If reading too high, check for
excessive carbon.
2. If reading too low, check,
a Cylinder head gasket
b. Cylinder base gasket
c. Piston, rings, cylinder.
Poor bottom end compression Check crankcase seals L and R
Blocked exhaust System
1 Check exhaust port carbon
formation.
2. Check exhaust pipe for internal
damage, excess carbon.
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