EASYKART:
THE ADJUSTMENTS |
HOW TO ADJUST THE CHASSIS ACCORDING
TO TRACK CONDITIONS AND BEHAVIOUR
FOREWORD
As far as chassis regulations are concerned, some preliminary
remarks are necessary.
First of all, it is important to know how to correctly predict
the behaviour of the chassis:
if we notice an oversteer with the chassis sliding to the
rear, we do not necessarily have to add more grip to the
rear axle. What might happen, actually, is that entering
the bend the chassis tends to go straight upsetting the
balance of the rear when the front axle stops sliding and
finds a better grip.
In addition, it is as important to know that physics sets
limits to kars: if I decide to act in a certain direction,
I am certain to upset the balance of another parameter.
The work done during the tests scheduled in view of a race
is aimed at finding the best compromise taking into account
as many of the necessary parameters as possible. Early in
the morning, with a still wet track and a low temperature,
it might turn out to be difficult to achieve the best set-up
for a race taking place in the early afternoon. While looking
for the best set-up, it is also important to do one thing
at a time: due to lack of time during practice, this simple
rule is often neglected even by the most experienced drivers.
This is a serious mistake, as we won’t be able to
understand the effectiveness of what we have done. From
this point of view, we recommend you do not alter the tyre
pressure, if the set-up has been changed.
EASYKART 60cc
Understeering
I widen the front track from 2 cm width to 2.5 cm on each
side.
Should this not be enough, I raise the chassis at the front.
The rear track stays as wide as possible, and to help it
slide more to the rear, I change the pressure by increasing
it step by step.
Oversteering
I reduce the front track from 2 cm to 1.5 cm.
I lower the chassis at the front and reduce the pressure
on the front axle.
Rain
I raise the chassis at the front and widen the tracks as
much as possible (up to the limits provided by regulations
–950mm) , reducing the rear by at least 3 - 4 cm.
The pressure of the rain tyres has to be between 1 and 1.8
bar, depending on how wet the track is: the more water there
is, the higher the pressure must be.
Slippery track
In addition to the above mentioned operations, depending
if the kart is understeering or oversteering, I reduce the
pressure of the 4 tyres down to a value of 0.8 - 0.9 bar
or, in any case, to less than the last time I entered the
track.
Grippy track
If the track has too much grip, the handiest solution is
gradually increasing tyre pressure.
The engine does not rev up
Normally, the Iame engine used in the 60 class should reach
14800 – 15000 revs.
Should the engine seem low on power and not rev up, a quick
test should be carried out by placing a hand and partially
covering the air horns: by doing this, I will enrich the
engine.
Two things can happen:
- the engine doesn’t rev up: the carburetion is too
rich and has to be leaned;
- the engine revs up: the initial carburetion was too lean
and has to be enriched
Warning: modifications to the carburettor screw have to
be made in 5-minute steps:
conventionally, the screw has to be turned by degrees corresponding
to 5 minutes on the clock face.
It is always important to keep the sparking plug under control:
if it is dirty and dark, the carburetion is rich, whereas
if it is too light you are lean.
Sometimes a set-up with too much grip penalizes the engine
performance as it starts to “bog”. In this case
the chassis has to be released a bit so that it slides better.
EASYKART 100/125cc
Understeering
Widen the front track 3 cm thick from the spacers.
Should this not be enough, raise the chassis at the front
.
Oversteering:
Reduce the front track and keep the chassis low at the front.
Rain
At the front, the chassis should be high with the front
track as wide as permitted (1120mm) , whereas the rear track
should be as narrow as possible, with hubs tight on the
axle. The front bar has to be removed to soften the chassis.
Tyre pressure ranges from 0.8 to 1.6 bar approximately,
depending on how much water there is on the track: the wetter
the asphalt, the higher the pressure should be. If the day
doesn’t look like it will clear up, the seat can be
raised, too (positioning spacers on the connection points
under the seat), but this operation cannot be done as quickly
if you have to change quickly from a rain set-up to the
standard dry set-up.
Slippery track
Should the track have too little grip, I will widen the
front and rear tracks and, if needed, raise the chassis
at the front.
Grippy track
The front track is widened by 2 cm and the chassis must
be low at the front.
In addition, the starting pressures must be a bit lower
than normal: with cold tyres, start with 0.6 bar.
The engine does not rev up
Normally, the Iame engine used in the 100 and 125 classes
should reach 15800 – 16000 revs.
Should the engine seem low on power and not rev up, a quick
test should be run by placing a hand and partially covering
the air horns: by doing this, I will enrich the engine.
Two things can happen:
- the engine doesn’t rev up: the carburetion is too
rich and has to be leaned;
- the engine revs up: the initial carburetion was too lean
and has to be enriched
Warning: modifications to the carburettor screw have to
be made in 5-minute steps:
conventionally, the screw has to be turned by degrees corresponding
to 5 minutes on the clock face.
It is always important to keep the sparking plug under control:
if it is dirty and dark, the carburetion is rich, whereas
if it is too light you are lean.
Sometimes a set-up with too much grip penalizes the engine
performance as it starts to “bog”. In this case
the chassis has to be released a bit trying to help it slide
better.
