APRILIA SX 125 User Manual

Checking the cylinder
•
Remove any scales formed by water in
the cooling interspace on the cylinder
(A).
•
Clean off any combustion deposits
from the outlet port (B).
•
Clean and check the groove of the O-
ring (C).
•
Make sure all threads (D) are in proper
conditions.
•
Make sure all the seal surfaces are
smooth and not damaged.
•
Check the cylinder wall for wear.
Ovality: max. wear limit 0.02 mm (0.0008 in).
Checking the piston
•
Check if there are marks of pinging/head knocking on the "squish" area and the piston cen-
tre.
•
Make sure the piston is not damaged or shows signs of pressure or galling.
SLIGHT SCORINGS CAN BE ELIMINATED BY RUBBING THEM WITH EMERY CLOTH (GRAIN 600
- 800).
•
Clean the piston crown and the bottom side as well as the piston ring grooves.
CLEAN THE RING GROOVES THOROUGHLY WITH A SCRAPER OR PREFERABLY WITH A
PIECE OF AN OLD PISTON RING.
•
Clearance between piston and wall = Cylinder diam. - Piston diam.; Nominal clearance 0.020
- 0.035 mm (0.00079 - 0.00138 in); Max. wear limit 0.080 mm (0.00315 in).
IF THIS WEAR LIMIT IS EXCEEDED, USE AN OVERSIZED PISTON OR REPLACE BOTH THE
CYLINDER AND THE PISTON.
WHEN THE PISTON IS REPLACED, ALSO REPLACE THE TWO SEEGER RINGS (1), THE PIN (2)
AND THE BALL RETAINER (3).
Engine RX SX 125
ENG - 108

APRILIA SX 125 Specifications

General

Displacement	124.2 cc
Cooling System	Liquid cooled
Fuel System	Electronic fuel injection
Transmission	6-speed
Rear Suspension	Monoshock
Front Tire	100/80-17
Rear Tire	130/70-17
Compression Ratio	12.5:1
Starter	Electric
Clutch	Wet multi-plate
Front Brake Disc	300 mm
Rear Brake Disc	220 mm
Dry Weight	134 kg
Bore x Stroke	58 mm x 47 mm
Max Power	11 kW (15 HP) @ 10, 000 rpm
Front Suspension	41 mm USD fork
Front Brake	Single 300 mm disc
Rear Brake	Single disc
Fuel Tank Capacity	7 liters
Frame	Steel perimeter
Engine Type	Single-cylinder, 4-stroke