Yamaha BEARTRACKER YFM250XC, Service Manual

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4 - 27
ENG
INSPECTION AND REPAIR
NOTE:
All valve springs must be installed with the
larger pitch
a
upward as shown.
1 Outer spring
2 Inner spring
4.Check:
●
Valve sealing
Leakage at valve seat
→
Reface, relap or
replace valve, relap.
Refer to “VALVE SEAT”.
*********************************
Valve seat checking steps:
●
Pour a clean solvent 1 into the intake and
exhaust ports.
●
Check the valve sealing, there should be
no leakage at the valve seat
2 .
*********************************
*********************************
Relapping steps:
●
Reassemble head parts.
●
Repeat lapping steps using fine lapping
compound.
●
Clean all parts thoroughly.
●
Reassemble and check for leakage again
using solvent.
●
Repeat steps as often as necessary to
effect a satisfactory seal.
*********************************
CAM SHAFT
1.Inspect:
●
Camshaft bushing
1
Wear/Damage
→
Replace.
4