Suzuki GSX-R750 Service Manual page 89

3-36 ENGINE
• If the seat width W measured exceeds the standard value or
seat width is not uniform, reface the seat using the seat cutter.
 Valve seat width W:
Standard: 0.9 – 1.1 mm (0.035 – 0.043 in)
If the valve seat is out of specification, re-cut the seat.
VALVE SEAT SERVICING
• The valve seats 1 for both the intake valve 2 and exhaust
valve 3 are machined to four different angles. The seat con-
tact surface is cut at 45°.
Seat angle
Seat width
Valve diameter 29.0 mm (1.14 in)
Valve guide I.D.

* The valve seat contact area must be inspected after
each cut.
* Do not use lapping compound after the final cut is
made. The finished valve seat should have a velvety
smooth finish but not a highly polished or shiny fin-
ish. This will provide a soft surface for the final seat-
ing of the valve which will occur during the first few
seconds of engine operation.
* The titanium valves are coated with an oxidized
membrane treatment to resist wear but the mem-
brane tend to be removed if lapped after valve seat
servicing.
NOTE:
After servicing the valve seats, be sure to check the valve clear-
ance after the cylinder head has been reinstalled. (  2-7)
• Clean and assemble the head and valve components. Fill the
intake and exhaust ports with gasoline to check for leaks.
• If any leaks occur, inspect the valve seat and face for burrs or
other things that could prevent the valve from sealing.

Always use extreme caution when handling gasoline.
INTAKE
30°, 45°, 60° 15°, 45°, 60°
0.9 – 1.1mm (0.035 – 0.043 in)
23 mm (0.91 in)
4.500 – 4.512 mm (0.177 – 0.178 in)
EXHAUST
60 ˚
60 ˚
˚
30
45 ˚
˚
15
˚
45