Anti-dive
front forks
Many high performance machines are fitted with anti-dive front
forks which lock when the brake is applied. In these cases the
front wheel will need to be placed against a solid object when
checking the damping.
It is important to distinguish between play in the forks and
that in the wheel bearings.
Light rubbing contact between a fork leg or damper body and
its shroud is acceptable.
Some smaller machines are not fitted with dampers on the front
suspension.
Some fork arrangements rely on the bracing incorporated in the
mudguard fixings to maintain their alignment. A mudguard insecurely
fixed to the forks may therefore adversely affect the handling
of the machine.
Light misting of the stanchion is
acceptable but if evidence of oil running down the fork leg
is apparent the reason for rejection would apply.
Pitting of a fork stanchion is not a reason tor rejection unless
damage to damper seals has occurred. It may be necessary to
pull back any rubber gaiters to conduct this examination if
it is possible without dismantling or damage but they must be
correctly refitted.
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1.
a. Check the condition, alignment and security of the front
fork assembly.
b. Check condition of suspension springs
c. Check shock absorbers for oil leakage due to seal failure
2. Check for wear in the front fork assembly by one of the following
methods:
a. whilst the machine is held upright grip the front wheel firmly
and attempt to turn the handlebars from side to side looking
for free play in the forks;
b. on leading or trailing link type suspensions, with the wheel
raised, attempt to move the swinging fork from side to side
and look for play in the pivot bearings or bushes.
3. With the front wheel raised check that the wheel and its
associated fixing and locking devices are present and secure
and that the wheel bearings are not excessively tight or do
not have excessive free play. Spin the wheel and listen for
roughness in the bearings.
4. Observe the freedom of movement and the effectiveness of
the damping by applying the front brake and depressing the forks
several times as far as possible. (see information column).
5. Check the security of the front mudguard and look for evidence
of it having been in contact with either the wheel, the tyre
or any fixed part of the machine.
6. Check condition of steering and suspension with regard to
corrosion. distortion and modifications.
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1.
a. a fork assembly component which is missing, loose, cracked,
or excessively bent, misaligned or corroded.
b. a road spring:
(i) incomplete, cracked or fractured
(ii) worn or corroded so that its cross sectional area is reduced
such that It is seriously weakened;
(iii) repaired by welding.
c. Oil leakage indicating failure of the seal.
2. Excessive free play between the sliding members of the forks
or in the pivot bearings, (see information column).
3.
a. a loose wheel spindle or securing nut(s) or locking device
missing or insecure
b. Excessive roughness, tightness or free play in the wheel
bearings
4.
a. fouling between the fixed and moving parts which affects
the movement of the forks, (see information column)
b. excessive stiffness in the movement of the forks
c. Forks with inadequate damping effect. (see information column)
d. an insecure fork brace
5. An insecure mudguard or one able to easily contact the wheel,
tyre or any fixed point of the machine.
6. deliberate modification which significantly reduces the original
strength, excessive corrosion, severe distortion, a fracture
or an inadequate repair of a load bearing member or its supporting
structure.
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