Overhauling Cylinder Head (Air-Cooled Engines) - Hatz 2-4L30 Workshop Manual

M 07.00 Cylinder head
M 07.20 Overhauling cylinder head (air-cooled engines)
- 1 - 2 - 6 - 7 -
Preparations:
– Removing cylinder head - see M 07.10.
Dismantling cylinder head:
– Place the cylinder head on the cente-
ring collar.
Note:
On the L 30, pull out the centering slee-
ves (81/1).
The cylinder head sealing face must not
be scratched or otherwise damaged; al-
ways use a soft cloth or similar underlay.
– Remove circlip (81/2) and pull off
rockers with shims (81/3).
– Press spring plate (81/4) down with tool
- 6 - and remove the valve spring collets
(81/5).
– Take out the valve springs with underlay
washers (81/6) and lift off the rocker
housing (81/7).
– Lift off the intermediate plate (81/8) and
take out the valve cone.
Checking parts:
– Check the valve guides and valve stems
for score marks and correct dimensions;
for values, see Section 4.
– Inspect the cylinder head for cracks (in
the metal webs) or an uneven sealing
surface.
– Renew the O-ring seals (81/9); on the
L 30, seal them with silicone.
– Check the valve seat rings and valve
cones for wear; for valve recess into
cylinder head, see Section 4.
– Check correct dimensions of rocker
bushing, rocker shaft and rocker pad
radius; for values, see Section 4.
81
3
L / M . . 09.96