BRP Johnson 4HP Service Manual page 87

Valve stem deflection
If unable to measure the valve guide inside diameter, mea-
sure the valve stem deflection.
 Dial gauge
Magnetic stand
1. Install the valves into the valve guide.
2. Lift the valves 8 – 10 mm off seat.
3. Move the valve head in the direction "X - Y" and measure
the deflection.
Valve stem deflection:
Service limit: IN and EX 0.35 mm (0.014 in)
If the measurement exceeds the service limit, replace the
valve and/or the valve guide.
NOTE:
For the valve clearance replacement, see the "VALVE
GUIDE REPLACEMENT" section on page 6-17.
Valve stem end
Inspect the valve stem end face for pitting and wear. If pitting
or wear is found, the valve stem end may be resurfaced.
If the chamfer of stem end has been worn away, replace the
valve.
POWERHEAD
VALVE / VALVE GUIDE
6-13