THE END OF THE CLUTCH (cheating) ERA

It seems that after CIK's latest decision of Dec 18th 2008 regarding clutches of KF2 & KF3, we will finally have equality, as far as the clutch is concerned. Those who so far managed to gain advantage (cheating) with the use of 'tuned' clutches will be forced to race on equal terms with the rest of us, until, of course, they find other ways to cheat!

HISTORY:

Before the KF engines were introduced, tuners lived in heaven with tuning possibilities in the areas of ports, metals, Conrad, transfers, exhausts and more. To their dismay, the KF homologations blocked the possibility on working in these traditional tuning areas and they had to find other things to offer.

Their new invention of tuning was the 'CENTRIFUGAL CLUTCH' that after some exploitation offers to the drivers a gain of 5 tenths per lap, even one second, depending on the track.

The tuners had very few and basic things to obey with such as the diameter, established by regulations minimum 80mm; weight given on each technical form for each engine; ability to move kart at not more than 5000 engine revs.

The thing is that also on testing, the commissioners were checking with digital rev counter while pressing down on gas pedal to make sure that the kart starts moving forward before 5000 revs. However, starting to move doesn't necessarily mean, that the centrifugal clutch has 'geared up' 100%, on the contrary. Besides, that drive torque speed is really not enough, and above all, it increases to its highest peak at around 11000 revs even at the sharpest turns, making automatic clutch skid as easy as possible. By machining the angle, springs and centrifuged masses you can let the clutch go on skidding over the 5000-rev mark.

What's the advantage? As the present 125 KF engines are practically 'dead' below the 8000 revs, letting them work at that speed before the clutch engages completely enables you to get a different thrust on drive wheels. But, this isn't all, allowing the clutch to skid until over 11000 revs, it has also been assessed that also at 9000 revs there is relative skidding between drive shaft and pinion, 10% - you get best drive torque and with it thrust is stronger too. This enables you to mount a final gear with one or two teeth less, making the most of this technical device.

What the tuners were offering, and at a very high price, (€1000 per clutch) was not irregular. They simply use a part of the international karting regulations that we can call 'shadow zone'. The initial regulations were stating that 'The engine clutch must be triggered at 5,000 rpm maximum and make the kart with the driver on board move forward.' What it wasn't saying is at how many rpm the clutch completely (100%) stops slipping and this is the 'shadow zone'.

WHO IS USING THESE CLUTCHES:

It must be said that the various KF engines use 2 types of centrifugal clutches. The first is the one that can be described as 'monolithic rotor with added friction material' and it is used by VORTEX and IAME (see photo 1).

The second one is of the type of 'rotor with springs with added friction material' and it is used by the other 2 major KF engines, which we are not naming for obvious reasons. (See photo 2)

It is said that you cannot 'tune' the type of clutch that is used by VORTEX and IAME but you can indeed 'tune' the one with the springs. This does not mean that all drivers using an engine other than VORTEX or IAME are using a 'tuned' clutch to gain false advantage. The majority of drivers are clean but there are few (and we are talking about fathers) who depend on such ways for giving joy to themselves and their sons. An expert in karting can recognize such instances by just listening to an engine screaming around tight turns or by observing a driver coming strongly out of a corner after a wrong entry which should have made his engine lose momentum.

INITIAL ACTIONS TAKEN BY THE LEGISLATORS:

With 'doped' results, which don't often give a true picture of the actual skill on the field, the legislators tried to find temporary ways of dealing with the problem. The first action taken was to amend the rules to set a maximum authorized threshold that the clutch slips . What they basically did, in the restricted time they had, was not only to set a method of checking whether the clutches trigger after the 5000 rpm point but also introduce a data logging system

To ensure that the slip of the clutch does not exceed the maximum authorised threshold (direct drive clutch, 100%, at 6,500 rpm maximum, under all circumstances).

Well this is very good news for the International events, but unfortunately on a national level, the local club authorities did not have the means neither the hardware to implement these changes. As a result we would see the scrutinisers at National races only checking whether the clutches trigger after the 5000 rpm point. BUT WHY DO THIS if you are not checking whether the slip of the clutch does not exceed the 6500 rpm threshold?