Tomberlin CrossFire 150, Service Manual

Page: 26 / 76

VALVE AND VALVE SEAT SEAL INSPECTION
The seal between the valve seat and valve can be inspected by coating the seat and valve seating surface with
layout fl uid or a magic marker.
• Put valve in seat; spin valve back and forth with very light pressure.
• Remove valve and inspect.
• The dye or marker should be wiped off all the way around the valve and seat sealing areas. If any marker is
still on the sealing area it will leak pressure.
VALVE AND VALVE SEAT LAPPING
If the inspection reveals leaks in the seal, the valve and valve seat should be lapped.
Notes:
Before lapping, clean up the valve, valve seat, and valve guide.
When lapping do not use too much force; press down the valve suction cup lever gently.
During lapping, do not drop any lapping compound into the place between the valve lever and the valve guide.
Lapping the valve seat:
• Spread a thin layer of lapping compound on the working bevel of the valve.
• Use a valve suction cup with rubber cup to catch up the top of the valve and repeatedly rub the valve suction
cup lever to lap the valve and valve seat evenly, until they match tightly.
• Lapping will clean small pits on sealing surface but if lapping does not clean up the seal you may have to
replace the valve and recondition the valve seat.
22