Yamaha LIT-11616-16-02, 5TE-F8197-10 service manual U T Ion, Lapping steps

CAMSHAFT, ROCKER ARMS AND VALVES

ENG

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Measurement steps:

●Apply Mechanic’s blueing dye (Dykem) b to the valve face.

●Install the valve into the cylinder head.

●Press the valve through the valve guide and onto the valve seat to make a clear pattern.

●Measure the valve seat width. Where the valve seat and valve face made contact, blueing will have been removed.

●If the valve seat is too wide, too narrow, or the seat is not centered, the valve seat must be refaced.

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9.Lap:

●Valve face

●Valve seat

NOTE:

After refacing the valve seat or replacing the valve and valve guide, the valve seat and valve face should be lapped.

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Lapping steps:

●Apply a coarse lapping compound to the valve face.

CAUTION:

Do not let the compound enter the gap between the valve stem and the guide.

●Apply molybdenum disulfide oil to the valve stem.

●Install the valve into the cylinder head.

●Turn the valve until the valve face and valve seat are evenly polished, then clean off all of the compound.

NOTE:

For best lapping results, lightly tap the valve seat while rotating the valve back and forth between your hands.

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