Adjusting Valve Clearance And Retightening The Cylinder Head Bolts; Measuring Exhaust Backpressure - Whisper Power M-SQ27 User Manual

TROUBLESHOOTING
5.4.2 Adjusting valve clearance and
retightening the cylinder head bolts
Both procedures have to be executed with a cold engine.
When both procedures are executed be sure to retighten
the cylinder head bolts before adjusting the valve clearance.
When retightening the cylinder head bolts, drain the coolant
by removing the coolant drain plug (ref. to fig. 4).
Loosen the bolts slightly, remove the rocker assembly (the
rocker arms, shaft, and stays) and then retighten the bolts
to the specified torque in the numerical order illustrated (ref.
to fig. 28).
Tightening torque cylinder head bolt:
Rocker stay tightening torque:
Fig. 28: Cylinder head bolt tensioning sequence
The clearance of both (intake and exhaust) valves should
be 0.25 mm in cold condition. Set the piston of the first
cylinder to be adjusted to top dead centre (T.D.C.) of
compression stroke.
The T.D.C. of compression stroke can be found by aligning
the T.D.C. mark "O" on the crankshaft pulley with the mark
on the gear case
First align the T.D.C. mark for the No. 1 cylinder. Confirm
that the valves do not move up or down when the crankshaft
is turned about 20 degrees in normal and reverse direction
of rotation.
Fig. 29: Checking valve clearance (turning)
If the rocker arms move piston no.1 is on the T.D.C. of the
intake or exhaust stroke. In such case turn the crankshaft
360° in the direction of engine rotation again. No. 1 piston
is now at T.D.C. of the compression stroke.
After adjusting the valves of cylinder 1 adjust the valve
clearance of the remaining cylinders in firing order 1-3-4-2
Turn the crankshaft 180º clockwise from the T.D.C of
cylinder 1 to the T.D.C of cylinder 3. Adjusts the valves of
cylinder 3 and turn the crankshaft further clockwise to the
T.D.C of cylinder 4 and finally to 2.
5.4.3
The exhaust system must be of adequate size -2 1/2"/ 63
mm - and maximal length (see installation manual). When
any doubt, backpressure has to be measured. An easy way
to measure for back-pressure is to use a water column.
118 ± 5 Nm
10-20 Nm
Fig. 30: Measuring exhaust backpressure
A water column can be made visible in a plastic tube along
a yardstick and fitting the end to a hose connection to fit in
the adaptor on the injection bend after removing the
exhaust temperature switch.
The bend A hanging down should not be to short helping to
damp the pulsating effect of the gas discharge. The water
column should be no more than 27 inches (69 cm.) of water
(1 PSI - 0,07 bar).

Measuring exhaust backpressure

A
MAXIMUM
69 cm
27 Inches