Suzuki DR-Z70 Service Manual page 172

Complaint
Engine runs poorly
in high speed range.
Dirty or heavy
exhaust smoke.
Engine lacks power.
Engine overheats
Symptom and possible causes
1. Weakened valve spring.
2. Worn camshaft.
3. Valve timing out of adjustment.
4. Too narrow spark plug gap.
5. Ignition not advanced sufficiently due to poorly
working timing advance circuit.
6. Defective ignition coil.
7. Defective pick-up coil or CDI unit.
8. Too low float-chamber fuel level.
9. Clogged air cleaner element.
10. Clogged fuel hose, resulting in inadequate fuel
supply to carburetor.
1. Too much engine oil in the engine.
2. Worn piston rings or cylinder.
3. Worn valve guides.
4. Scored or scuffed cylinder wall.
5. Worn valves or stems.
6. Defective stem seals.
7. Worn oil ring side rails.
1. Loss of valve clearance.
2. Weakened valve spring.
3. Valve timing out of adjustment.
4. Worn piston rings or cylinder.
5. Poor seating of valves.
6. Fouled spark plug.
7. Incorrect spark plug.
8. Clogged jets in carburetor.
9. Float-chamber fuel level out of adjustment.
10. Clogged air cleaner element.
11. Sucking air from intake pipe.
12. Too much engine oil.
13. Defective CDI unit.
1. Heavy carbon deposit on piston crown.
2. Not enough oil in the engine.
3. Defective oil pump or clogged oil circuit.
4. Too low in float chambers fuel level.
5. Sucking air from intake pipe.
6. Use of incorrect engine oil.
7. Clogged air intake with dust.
SERVICING INFORMATION
Remedy
Replace.
Replace.
Adjust.
Adjust.
Replace CDI unit.
Replace.
Replace.
Adjust.
Clean.
Clean and prime.
Check oil level and drain
out excess.
Replace.
Replace.
Rebore or replace.
Replace.
Replace.
Replace.
Adjust.
Replace.
Adjust.
Replace.
Repair.
Clean or replace.
Adjust or replace.
Clean.
Adjust.
Clean.
Retighten or replace.
Drain out excess oil.
Replace.
Clean.
Add oil.
Replace or clean.
Adjust.
Retighten or replace.
Change.
Clean.
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