Inspecting The Cylinder Head - Derbi Rambla 250 Manual

Engine
AP8140921 Oil seal punch
AP8140660 Piston fitting ring

Inspecting the cylinder head

- Using a trued bar and a thickness gauge, check
that the cylinder head surface is not worn or dis-
torted.
Maximum run-out allowed: 0.05 mm
- Check that the camshaft and the rocker pin bear-
ings show no sings of wear.
- Check that the cylinder head cover surface, the
intake manifold and exhaust manifold are not
worn.
Characteristic
bearing "A"
Ø 12.000 ÷ 12.018
bearing "B"
Ø 20.000 ÷ 20.021
bearing "C"
Ø 37.000 ÷ 37.025
Inspecting the timing system components
- Check that the guide slider and the tensioner pad
are not excessively worn.
- Check that the chain assembly, the camshaft
driving pulley and the sprocket wheel are not worn.
- If sings of wear are found, replace the parts; if the
chain, pinion or pulley are worn, replace the whole
assembly.
- Remove the central screw with the washer and
the tensioner spring. -Check that the one-way
mechanism is not worn.
- Check the condition of the tensioner spring.
- If signs of wear are found, replace the whole as-
sembly.
ENG - 116