Rotax 912-UL Repair Manual page 27

6.6.2)Disassembly of cylinder head:
Remove circlips 12xl from rocker arm shaft O but don't overstress circlip. Take off
both rocker arms from shaft.
I NOTE:
Rocker arm shaft is pressed symmetrically into position on head.
Compress valve spring by utilizing fitting jig g 877 380 and clamp 0 or similar tool
and removevalve cotters. Release valve spring and remove both springs and spring
retainer, and withdraw valve.
O NOTE:
Prior to the removal of valve,
clear off any burrs possibly
present, to prevent any dam-
age to stem seal and guide.
Mark valves coordinately.
Repeat procedure for the removal of second
valve and clean cylinder afterwards. Visual
check of oil tubes for tightness. If
leaking, exc han ge respectively.
For this renewal heat up cylinder to
approximately 180oC (360'F).
Extract tubes and remove any
glue residue from bore. Apply
LOCTITE 648 to both flutes of
tube and twist andpush tubeinto
position. Apply LOCTITE only
on cold tube.
I ATTENTION: If sealingface
to cylinder
showsanyoil
carbon residues, remove them carefully. Check sealing face for
roughness. At re-assembly coat sealing face thinly with LOCTI-
TE2 2 t.
At slight wear, valve and valve seat may be re-ground, using emery paste. Because
of seat iumour, restrict re-grinding to 0,2 mm (.008 in.) maximum. Clean cylinder
head and single components in gasoline orkerosene. Check sealing face of cylinder
head, and if need be, true-up along with cylinder, but only slight rework is allowed.