BMW 630CS - Page 78

78 Valve clearances, air cleaner, intake air preheat
The compression stroke top dead center
for each cylinder is obtained when the
valves of the cylinder n`ext but one in the
firing order are on the overlap.
Compression
stroke TDC
-cyl. NO.
1
5
3
6
2
4
Valve overlap
in cylinder
NO.
6
2
4
1
5
3
To adjust valve clearance at the rocker,
Ioosen the riexagon nut (10 mm wrench).
Turn the eccentric with a piece of 2.5 mm
diameter wire bent to a slight angle, until
the specified clearance is obtained.
Tighten hexagon nut and check that
clearance has not altered.
lnstalling alr cleaner (BMW 630 CS):
Connect the plug (4) from the heat-sen-
sitive switch and the secondary breather
line (3). Place the air cleaner on the upper
section of the carburetor. Connect the
primary breather (2) and the intake air
preheat pipe (1). Attach the air cleaner
housing with the cap nut.
lnstalling air cleaner with airllow meter
(BMW 633 Csi):
Place air cleaner with airflow meter in
mountìng. Connect plug (2) at airflow
meter. Push flexible gaiter on to throttle
butterfly stub pipe, and tighten hose
clip (1 ).
The automatic ]ntake air prehea( f lap
valve (1) on the BMW 630 CS i§ installed
in the intake pipe of the air cleaner anc
§jlencer, and is opened and closed by an
expansible element (2). During a BMW
[nspection every 15000 km (10000 miles).
check correct operation and free
movement of the flap valve and element.
and oil the pivots if necessary. When the
flap valve is closed, air already preheatea
by the exhaust manifold is drawn into
the engine. As the outsìde temperature
rises above approx. 15° C (59° F), the
flap valve opens and the supply of
preheated air is discontinued.