APRILIA RS 125 Manual page 280

TROUBLESHOOTING INFORMATION
Engine is burning oil
Loss of engine power
Engine overheats
9 - 4
Oil pump out of adjustment.
Crankshaft seal damaged or worn.
Piston rings or cylinder worn.
Incorrect air gap between spark plug electrodes or ignition
system faulty.
Carburetor jets obstructed.
Incorrect fuel level in carburetor float chamber.
Air cleaner clogged.
Air leaking past the intake duct.
Engine is receiving too much oil.
Too much carbon build-up on piston crown.
Engine is receiving insufficient oil.
Oil pump faulty or oilways obstructed.
Fuel level in carburetor float chamber too low.
Air leaking into intake duct.
Engine oil used does not meet specification.
Cooling system faulty.
RS 125
Adjust.
Replace.
Replace.
Adjust or replace.
Clean.
Adjust.
Clean.
Tighten or replace.
Adjust the oil pump.
Clean.
Adjust the oil pump..
Replace or clean.
Adjust.
Tighten or replace.
Use specified oil..
Read radiator section.