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Drawbolt
2
Rear wheel sprocket
3
Bonded rubber bush -4 off
4
5
Rear hub
6
Spacer
7
Wheel rim
8
Tyre (3.00x17-6PR)
tion
1
The rear chain on CG125 models derives considerable
benefit from
its
complete
motorcycle is subjected to considerable loading in normal use,
in addition to which the unfortunate dictates of fashion have
resulted in the almost universal adoption of a small and inade-
quate guard covering the top run of the chain only. The full
enclosure of the CG125 means that the chain is operating in
almost ideal conditions, and this should be reflected in
remarkably long chain life.
2
A small inspection plug is provided through which chain
tension can be checked, and intermediate lubrication can take
place. It is important that the drain holes in the bottom of the
case are kept clear of obstruction, otherwise any water which
finds its way into the enclosure will accumulate at the bottom of
the case, giving rise to running conditions worse than complete
non-enclosure.
3
Periodically the tension will need to be adjusted, to com-
pensate for wear. This is accomplished by placing the machine
on the centre stand and slackening the rear wheel spindle nut
so that the wheel can be drawn backward by means of the
drawbolt adjusters in the fork ends. The rear brake torque arm
bolt must also be slackened during this operation. The chain is
in correct tension if there is approximately 20 mm ( f in) slack
in the middle of the lower run. Always check when the chain is
at its tightest point as a chain rarely wears evenly during
service.
4
Always adjust the drawbolts an equal amount in order to
preserve wheel alignment. The fork ends are clearly marked
with a series of horizontal lines above the adjusters, to provide a
simple, visual check. If desired, wheel alignment can be checked
by running a plank of wood parallel to the machine, so that it
touches the side of the rear tyre. If wheel alignment is correct,
Chapter 5 Wheels, brakes and tyres
Fig. 5.3. Rear wheel and hub - component parts
9
Inner tube
13
16
enclosure.
The
chain
of
the plank will be equidistant from each side of the front wheel
tyre, when tested on both sides of the rear wheel. It will not
touch the front wheel tyre because this tyre is of smaller cross
section. See accompanying diagram.
5
Do not run the chain overtight to compensate for uneven
any
wear. A tight chain will place undue stress on the gearbox and
rear wheel bearings, leading to their early failure. It will also
absorb a surprising amount of power.
6
After a period of running, the chain will require lubrication.
Lack of oil will greatly accelerate the rate of wear of both the
chain and sprockets and will lead to harsh transmission. The
application of engine oil will act as a temporary expedient, but it
is preferable to remove the chain and clean it in a paraffin bath
before it is immersed in a molten lubricant such as 'Linklife' or
'Chainguard. These lubricants achieve better penetration of the
chain links and rollers and are less likely to be thrown off when
the chain is in motion.
7
To check whether the chain is due for replacement, lay it
lengthwise in a straight line and compress it endwise so that all
the play is taken up. Anchor one end and measure the length.
Now, pull the chain with one end anchored firmly, so that the
chain is fully extended by the amount of play in the opposite
direction. If there is a difference of more than ^ inch per foot in
the two measurements, the chain should be replaced in con-
junction with the sprockets. Note that this check should be
made after the chain has been washed out, but before any
lubricant is applied, otherwise the lubricant may take up some
of the play.
8
When replacing the chain, make sure that the spring link is
seated correctly, with the closed end facing the direction of
travel.
9
An equivalent British-made chain of the correct size is avail-
able from Renold Limited. When ordering a new chain always
quote the size (length and width of each pitch), the number of
links and the machine to which it is fitted.
20 Bearing
22 Spoke set
23 Spoke set
16
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