4 - ENGINE
107
Steps for seating valves:
- Apply a fine abrasive paste (grinding paste) to the valve
seat.
DO NOT ALLOW THE PASTE TO
PENETRATE IN THE SPACE BET-
WEEN THE VALVE STEM AND
THE VALVE GUIDE.
- Apply acid with molybdenum disulphate to the valve stem.
- Fit the valve into the cylinder head.
- Rotate the valve until its face and its seat are uniformly
ground, then remove all the paste immediately.
TO OBTAIN THE BEST RESULTS
FROM GRINDING THE VALVES,
ROTATE THE VALVE GENTLY IN
THE VALVE SEAT WHILE RO-
TATING IT BACKWARDS AND
FORWARDS WITH THE HANDS.
- Apply a coarse abrasive paste to the valve face and repeat
the above steps.
ENSURE THAT THE ABRASIVE
PASTE IS COMPLETELY CLEA-
NED FROM THE VALVE FACE
AND SEAT AFTER EACH VALVE
GRINDING OPERATION.
- Re-apply blue mechanical dye (Prussian blue) to the valve
seat (b).
- Fit the valve into the cylinder head.
- Press the valve through the valve guide and against its seat
to obtain a good contact.
- Measure the width of the valve seating (c) once again.
Grinding correct => Refit valves.
- Check tightness of valve seating.
Tight valve seating => Refit cylinder head.
CAUTION
N.B.
N.B.
Summary of Contents for GPR 125 Racing
Page 1: ...WORKSHOP MANUAL GPR 125 4 stroke ...
Page 169: ...6 COOLING SYSTEM 169 6 1 DIAGRAM OF THE SYSTEM ...
Page 170: ...6 COOLING SYSTEM 170 ...
Page 179: ...7 LUBRICATION SYSTEM 179 7 1 DIAGRAM OF THE SYSTEM ...
Page 180: ...7 LUBRICATION SYSTEM 180 ...
Page 192: ...8 CHASSIS 192 FITTING FRONT SUSPENSION ...
Page 202: ...9 BRAKING SYSTEM 202 9 BRAKING SYSTEM FRONT BRAKE REAR BRAKE 203 211 9 1 9 2 ...
Page 247: ...Rev 0 2009 ...