Yamaha VMX12HC (1995) [146/405] Inspectio n and repair

INSPECTION AND REPAIR

NOTE:

After installing valve guide:

*U se the 5.5 mm Valve G uide R eam er

(YM -

01196) to obtain proper valve guide/

valve stem clearance,

the valve seat.

Circ lip

Valve guide

Valve S eat

Inspect

*V a lve seat

W ear/Pitting/Valve replacem ent

Resurface seat at 45° angle.

Clean valve seat if pitted or w orn using a 45°

Valve

Seat

Cutter (YM -91043) , When twist-

ing cutter, keep an even dow nw ard pressure to

prevent chatter m arks.

Cut sections as follow s

Section

Cutter

30°

45°

60°

2. M easure:

• Valve seat width

3. Apply:

• M echanics bluing dye (D ykem )

To valve and seat.

*F ine grinding com pound (sm all am ount)

Ground surface of valve face.

4. Position:

Into cylinderhead.

Spin it rapidly back and forth, then lift

valve and clean off all grinding com pound.

5. Inspect:

seat surface

W herever valve seat and valve face m ade

contact, bluing w ill have been rem oved.

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