Sym PA12B Service Manual page 109

7. Cylinder Head / Valve
Rotate the valve seat cutter clockwise and
counterclockwise with 4 to 5 kg pressure in
order to fix the uneven part.
Caution
Apply motor oil to the contact face while
grinding it.
Use the 45 degree valve seat cutter to remove
any roughness on the valve seat.
Caution
Use the 45 degree valve seat cutter to
grind the seat after changing the valve
guide.
Use the 32 degree cutter to remove the upper
1/4 part of the valve seat.
Use the 60 degree cutter to remove the
bottom 1/4 part of the seat and check the new
valve seat.
7-12
To this chapter contents
4~5kg
45°
Old valve seat
width
32°
Old valve seat
width
60°