Honda C72 Shop Manual page 60

6. FRAME
Construction of frame body
The frame supporting engine contacts with ground through the front and reor wheels and
is the skelton of whole chassis. Further it has important feature affecting its form and
design. The main function of frame is to maintain chassis strength, supporting engine,
rider, and load on the carrier, and has to endure shock due to roughness of rood through
tyre and shock absorber.
On th e other hand it requires rigidity from viewpoints of control ability, and further req ui res
light weight to attain better running performance. The frame body of Hondo 250 • 300
Model
C72,
77 is, mode of steel of stress skin construction and adopted such croSs sec-
tionGI form as refreg erato r having round corner. Th e type of form has high strength to
bending moment a nd torsion. Th erefore this would be most favorable form of construc-
tion for mo'tor cycle frame having high rigidity from manufacturing viewpoints.
Especially welding is done by new type of seam welder to attain reliable connection and
also uniform products having beautiful outlook. On the other hand for the frame of
Model CB72, 77 , as main strength members, hi gh corban steel tubings were adopted to
attain li ght weight and to increase rigidity.
2
CD
Gasoline tank
®
Corrier
@
Spare seat
®
Rear fender stay
®
Reor fender
QD
Shock obsober
CV
Rear fork
®
Seal box
®
Frome body
Fig . 6 - 1. Frame body for Model C72, 77.
118
/
CD
Main pip e
@
Coil sett ing plate
@
Tube holder
o
R. sub-tube
®
Battery support Stay
®
Sub-tube cross-member
CV
R. sub-tube ho lder
'8' R.l . rear cushl'on
\V upper
bracket
®
l . sub·tube holder
@ R. bottom plate
@
R. ste p holder p iece
@
Muffler setting pipe
@ Center p ipe
@ Steer ing head pipe
@
Fuel tonk ho lder
@
Key ho le
Fig. 6- 2 . Fr ome body for CB72, 77.
119
@
Front down tube
@
Drivers tube
®
Engine hanger plate
®
l. sub-tu be
@
Main switch bradet
@
l . bottom p late
@
Center pipe bushing
®>
l. step holder piece