Checking Valve Spring Seal; Checking The Cam Levers; Checking Cylinder Head - KTM 450 SX-F EU Repair Manual

301ENGINE - WORK ON THE INDIVIDUAL PARTS
147
Cbeckinl valve ~ rinl
seat
500173-01
Cbackinllha cam lavars
301227-10
400375-10
400373-10
- Check the valve spring seat for breakage and wear (visual check).
• If the valve spring seat is broken or worn:
- Change the valve spring seat.
- Measure the thickness of the valve spring seat.
1 Valve spring seat - thickness 11.4 ... 1.5 mm (0.055 ... 0.059 in)
• If the measured value does not meet specifications:
- Change the valve spring seat.
- Check the cam levers and cam lever shafls for damage and wear.
• If there is damage or wear:
- Change the cam levers and/or cam lever shafts.
- Check the valve guides with the special tool
1 Limit plug gauge (59029026006) (-- p. 230)
• If the special tool is easy to insert into the valve guide:
- Change the valve guide and valve.
Check the sealing area of the spark plug thread and the valve seals from damage
and cracki ng.
• If there is damage or cracking:
- Change the cylinder head.
- Using a straightedge and the special tool, check the sealing area of the cylinder for
distortion.
1 Feeler gauge (59029041100) (-- p. 230)
Cylinder/cylinder head - distortion of
sealing area
0: 0.10 mm (0: 0.0039 in)
• If the measured value does not meet specifications:
- Change the cylinder head.
- Check sealing seat of the valves.
Valve - sealing seat width
Intake 1.50 mm (0.0591 in)
Valve - sealing seat width
Exhaust
1.50 mm (0.0591 in)
• If the measured value does not meet specifications:
- Machine the valve seat.
- Blowout all oil holes with compressed air and check that they are clear.