Checking Valve Seats For Wear - APRILIA M192M Workshop Manual

ENGINE
3.6.24.

CHECKING VALVE SEATS FOR WEAR

•
Measure "V" mark depth on valve seat. Max. wear limit
1.6 mm.
•
Clean valve guide from any carbon deposits.
•
Measure the inner diameter of all valve guides (D).
•
Make the measurements at three different heights in
the rocker arm thrust direction.
Exhaust valve guide
D = Standard diameter: 5.000 ÷ 5.012 mm
D = Allowed limit: 5.022
Intake valve guide
D = Standard diameter: 5.000 ÷ 5.012 mm
D = Allowed limit: 5.022
• If the valve seat mark depth values or the valve guide
diameter are above the specified limits, change the
head.
Checking valves
• Check valve stem diameter (d – D) in the three points
shown in the figure.
Standard diameter
D1, D2 and D3=Intake: 4.972 ÷ 4.987 mm
d1, d2 and d3=Exhaust: 4.96 ÷ 4.975 mm
Min. allowed diameter
D1, D2 and D3=Intake: 4.96 mm
d1, d2 and d3=Exhaust: 4.95 mm
•
Calculate clearance between valve and valve guide.
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Engines M192M / M191M / M245M / M234M / M282M / M281M