Valve Guide Replacement - BRP Johnson 4HP Service Manual

NOTE:
Clean and assemble the cylinder head and the valve compo-
nents.
Fill the intake and the exhaust ports with solvent in order to
check for leaks between the valve seat and the valve.
If any leaks occur, inspect the valve seat and the face for
burrs or other things that could prevent the valve from seal-
ing.

Valve Guide Replacement

Be careful not to damage the cylinder head when replac-
ing the valve guide.
1. Using the valve guide remover, drive the valve guide out
from the combustion chamber side toward the valve
spring side.
 Valve guide remover and installer
NOTE:
Do not reuse the valve guide once removed.
Always use a new oversize valve guide when assembling.
2. Ream the valve guide hole with the φ9,3 mm reamer in
order to true the hole and remove burrs.
 Valve guide reamer (φ9,3 mm)
Reamer handle
NOTE:
Turn the reamer clockwise, never counterclockwise.
3. Lubricate the new oversize valve guide.
4. Using the valve guide installer, drive into the valve guide
from the valve spring side toward the combustion cham-
ber side. Position the valve guide as shown in the figure.
 Valve guide remover and installer
Valve guide protrusion H: IN and EX 11.0 mm (0.3 in)
POWERHEAD
VALVE / VALVE GUIDE
6-17