Cylinder Head - Disassembly - Rotax 912 Series Maintenance Manual

3.11) Cylinder head - disassembly

See Fig. 72-59.
If the rocker arms are to be dismantled without removing the cylinder head, turn
the crankshaft to set the piston of the respective cylinder to ignition T.D.C. so
that only little pressure remains on the rocker arm. Depress rocker arm with
check lever part no. 877690 towards the hydraulic valve tappet. Now the rocker
arm is completely released and the rocker arm shaft can be removed.
◆ NOTE:
Withdraw rocker arm shaft and remove both rocker arms.
◆ NOTE:
Compress the valve springs using valve spring mounting device (1), part no.
877380, valve spring mounting pliers (2) or similar tool and lift out valve cotters.
Release valve spring. Remove valve spring retainer and both springs and
withdraw valve.
◆ NOTE:
Repeat procedure for the second valve. Clean cylinder head.
Check oil return tubes for leaks (visual inspection). If there is leakage in area (3),
the respective oil return tubes must be replaced. For this procedure, heat the
cylinder head to max. 180 °C (360 °F). Extract the oil return tubes and remove
any glue residues from the bore. Apply LOCTITE 243 on the new oil return tubes
in the area of the two grooves and twist and push tube into position in the
preheated cylinder head.
◆ NOTE:
Effectivity 912/914 Series
Edition 1 / Rev. 0
BRP-Rotax
Maintenance Manual
Never use force to press out the rocker arm shaft. The hexagon
of the collar cap nut may be in an unfavorable position and
prevent removal of the rocker arm shaft. In this case, loosen the
nut.
Newer engine versions have plastic bushings as bearings.
These plastic bushings must be laid aside in an ordered manner
to prevent any mixup.
Prior to removal of valves, clear burrs which may be present on
valve stems to prevent damage to valve stem seal and valve
guide. Mark valves coordinately.
Only apply LOCTITE 243 on cold parts!
72-00-00
page 57
May 01/2007