Fig. 27. Clearance rocker - rocker shaft
5.
Check that the rocker bearing surfaces are not out-
of-round worn.
Calculate the clearance between the rocker and
shaft. The clearance must not exceed 0.2 mm
(.0078 in).
Check that the ball pin's spherical part is not defor-
med or worn. The threads should be undamaged
on the pin and lock nut. The locknut should be in
good condition.
The mating sphere of the rockers (against the val-
ve) must not be unevenly worn or concave. Adjust-
ment for minor wear can be made in a grinding
machine.
Note: MD2O10-2030. A new type of rocker (includ-
i
ng valve cap) has been introduced as from engine
number:
MD2010: 5101202984
MD2020: 5101308898
M D2030: 5101465653
Only the new type of rocker is available as a spare
part. If one or several of the older type of rocker
need to be replaced, all the rockers must be re-
placed at once, and valve caps installed on the
valve stems.
Fitting of cylinder head
Fig. 28. Fitting of valve stem seals
1.
Press down new valve stem steals on the valve
guides.
Note:
MD2030 and MD2040 have different seals
for the guides for the inlet and outlet valves.
Engine body
00
C
c
2
Fig. 29. Fitting of valves
1.
Valve lock
3.
Valve spring
2.
Valve spring retainer
5.
Valve cap*
4.
Valve
*
MD2040 and later versions of MD2O10, 2020, 2030
2.
The valves should be fitted in the correct order. Oil
i
n the valve spindles and fit the valve in its guide.
Place the valve spring and retainer in position and
press the spring together with a valve spring ten-
sioner. Fit the valve lock.
Note:
Observe care when fitting the valves and
compressing the springs so that the valve stem
seals are not damaged.
Fit the valve caps when all valves are fitted. (Ap-
plies to MD2040 and later versions of MD2O10,
MD2020, MD2030 (Please refer to the note below
i
tem 5)).
Fit new plugs if these have been removed.
3
1
Comparison between new and old rockers
1.
Earlier rocker 4. The new rocker tip
2.
Earlier rocker tip
5. Valve cap
3.
3.
The new rocker
6. Valve
4.
6.
Oil in the rocker mechanism and fit the different
parts.
To Next Page
Loading...
