Honda CB450 1968 Service Manual page 37

26
I
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fig. 3. 36
Tachometer gear box, pinion and washer
CD
Pinion
@
Wosher
@
Gear box
Fig. 3. 37
Installing the gear box assembly
CD
Gear box assembly
Fig. 3. 38
Valve spring component ports
CD
Torsion bar IVolve springl
@
Torsion bar outer
@
Torsion bar holder
©
Torsion bar outer orm
3. ENGINE
EXHAUST SIDE
1. Assemble the cam follower and cam follower
shaft into the cylinder head.
2. Install the exhaust camshaft.
3. Assemble the pinion on the tachometer gear
box. Do not forget to install the washers.
(Fig.
3. 36)
4. Install the gearbox assembly. Firmly set the
convex section of the tachometer pinion into the
camshaft groove. (Fig.
3. 37)
5. Install the breaker point base.
NOTE:
Upon completion of the installation, check to
make sure that the camshaft rotates freely.
6.
Install the spark advancer and the contact
breaker assembly.
7. Temporarily tighten the lock nut.
NOTE:
If the side clearance of the camshaft is exces-
sively large, noise will result, and if the clearance
is too small the shaft may sieze. The proper
clearance is 0.05 to 0.35mm (0.002~0.014inl.
Shims for adjusting the camshaft side clearance
are available in 0.1 mm and 0.2mm (0.004 and
0.008 in} in thickness.
J.
Valve and Torsion Bar Spring.
When a bar is subjected to torsion, a reaction
to this force is created in the opposite direction.
This model utilizes torsion bar principle in the valve
spring.
The use of the torsion bar valve spring has
eliminated spring surging, aim further, the maximum
valves spring load of 79 kg ( 174.2 lbl hos been
contained in a very small space.
This has enabled the valve mechanism to be made
compact. On one end of the torsion bar an arrow
is maked, when assembling the valve spring the
torsion bar is twisted in the direction of the arrow
to provide the spring prelood.
This is necessary because the preset has been
incorporated in the torsion bar.
Exersize care when handling the torsion bar oasr
even a small scratch or scar may cause torsionb
to
foil.