Honda C65 - Engine Adjustments and Timing Checks

6. 7
PER IODICAL ADJUST
6.
DIC ADJUSTMENT
6.
NANCE INSPECTION
- e· die in sp ections should be performed at regular
s:::·ec le and designa ted mileages in order to obtain
scrisfocto ry service as well as to extend the useful
lif e from y our motorcycle.
A. ENGINE ADJUSTMENT
l . MEASURING COMPRESSION
A low compression pressure will result in a cor-
res ponding drop in the engine power output. Pressure
le ak from any cause ma y effect the engine s peed
adiustment at l ow speed and cause engine stall.
a. Remove
the spark plug .
b.
In sert the end of the compression gauge into the
spark plug hole and hold firmly to pre vent pre -
ssure from leaking. (Fig. 6-1}
c. Operate the kick starter rep eatedl y sev era l times
with both th e choke and thr ottle in the full o pe n
position.
(Caution}
CD Make sure that the throttle and choke ar e
f
ully opened, or else, a lower press ure i ndi-
c ation will be registered on the compression
gauge .
Compression gauge
Figure 6- 1. M eas uring co mpr ession pr es sure
® The cylinder comp re ss i on pressure indi ca ti on k Stanaarcr •q;,r. :r.
w ill gradua lly in creas e w ith each kick, th ere-
fo re , continue kicking until the pressure
stabi
liz es at the highest point.
® To obtain a true cylinder pressure indi c ation .
the measureme nt s hould be made after th e
engine
attain s ope rating temperature .
@ Che ck for the pr op er opera ti on of the va lves.
@ Ma ke s ure that the co mpr ess ion gauge is firmly
fi
tt ed in the s park plug ho le.
d. The s tandard spec ified cy linder co mpr ess ion pressure
is 1
2kg/c m
2
1172 lb / in
2
). (Fig. 6-2}
e. In case the compression pressure exceeds 1 4kg/ cm
2
1200 l b/ in
2
), it is an i ndication of heavy c arbon
de posit accumulation on the cy linder he ad or the
pi sto n. The dep osits sh ou ld be removed by disa-
ssemblying the cylin de r head from the cy linder.
f.
When the co mpre ss ion pressure registers le ss than
9kg/cm
2
1128 lb / in
2
),
it is an indicati on of pr ess ure
leak. Firs
t, check the tappet adiustment and see ifj ~
the condition can be co rre cted, di sassemble th e
engine
and inspect the condition of th e va lves, the
head gasket and pist on rings.
2. TAPPET ADJUSTMENT
85