Takeuchi TB 175 Handbuch Seite 753

2. Inspection and adjustment
(4) Intake/exhaust valve clearance adjustment
Make measurement and adjustment while the engine is
cold.
(a)Valve clearance measurement
1)Remove the rocker arm cover above cylinder head.
2)Set the No.1 cylinder in the compression TDC
Turn the crankshaft to bring the piston of the No.1 cyl-
inder to its compression top dead center while watch-
ing the rocker arm motion, timing scale and the top
mark position of the crankshaft pulley.
(Position where both the intake and exhaust valves
are closed.)
Notes:
• The crankshaft shall be turned clockwise as seen from
the radiator side.
• The No.1 cylinder position is on the opposite side of
the radiator and the ignition order shall be 1-3-4-2-1 at
180° intervals.
• Since the intake and exhaust valve rocker arms are
operated the same and there is a clearance between
the arm and valve generally at the top dead center, the
position can be checked by means of the play when
the arm head is held with a hand. Also see that the
crankshaft pulley top mark is positioned at zero on the
timing scale. If there is no valve clearance, inspection
in the disassembled state is necessary since the valve
seat may be worn abnormally.
3)Valve clearance measurement
In case of 2-valve cylinder head insert a thickness
gage between the rocker arm and valve cap, and
record the measured valve clearance.
In case of 4-valve head insert a thickness gage
between the rocker arm and the valve bridge, and
record the measured valve clearance.
(Use it as the data for estimating the wear state.)
4)Adjusting other cylinders
In case of 4-cylinder engines, turn the crankshaft
180° and make adjustment for the No.3 cylinder.
Then adjust the No.4 and No.2 cylinders in this order.
The cylinder to be adjusted first does not have to be
the No.1 cylinder. Select and adjust the cylinder
where the piston is the nearest to the top dead center
after turning, and make adjustment for other cylinders
in the order of ignition by turning the crankshaft 180°
each time.
In case of 3-cylinder engines, turn the crankshaft
240° and make adjustment for the No.3 cylinder.
Then adjust the No.2 cylinder in this order.
No.1 cylinder
Top mark
Rocker arm
Valve
clearance
Valve clearance (2-valve head)
Valve clearance Rocker arm
Valve bridge
Valve clearance (4-valve head)
40
Crankshaft
4TNV94L pulley
Rotational direction
Top mark
Adjusting screw
Lock nut