Columns: On Track

Some advice on what to do on our kart and how to tackle the first trips to the track after a forced winter break.

Report and photos M.Voltini

Let’s have a look and see what mechanical jobs may need doing beforehand, and which are the regulating norms that will enable you to tackle a circuit, which has also been closed for some time, and that may have dirty asphalt or very likely little grip. Among other things, the latter must be born in mind if we are racing with new material. So, no disappointment if our chassis seems to pull in two directions, nor let yourself be carried away with enthusiasm if you seem to be flying round on two tracks: when the temperature gets higher, you will undoubtedly find that the kart responds differently to how it does during these early days of the year.  

The first time that you go to the track is often also for trying out any new innovations concerning technical regulations for our category that is if we are professional drivers. However, this year we can be quite settled from this point of view: in fact, with the exception of the national 60 cc class (about which we will say a bit more in an article apart in this same issue of Vroom) there aren’t any important changes. With the new three-year homologation for tyres, we are going to have new tyres, but just for the international classes. Moreover, these are elements that must be tried or changed directly on the circuit; therefore, there isn’t much to say about what you should do the kart. Also the influence of this innovation with national classes is relative, either because factories like Vega haven’t changed their products much, or because in several classes the same tyres mounted is a decision, which is independent of Cik decisions. The only exception is for the Under 18: as in the World Championship they have passed to LeCont, due to a tender, also the corresponding class of the Parolin Trophy di Marca (Brand Trophy) has adapted to the situation. Likewise, the Rok Cup has adopted a new tyre, the YLR ROK, always made by Bridgestone, but we don’t think that it is a product that changes kart response radically: also in this case, the direct results on the track might bring about some change in set up, but nothing to worry about beforehand. As for the rest, apart for the Rotax Max where front brakes are not allowed, it seems that there are no important technical changes in the other direct drive classes. Therefore, from this point of view we can all rest assured that there’s nothing to worry about; unless there are afterthoughts and last minute changes, and it won’t be the first time that this has happened. The only thing is that if up till now we have been able to get on the track for normal tests without mounting plastic rear bumpers, obviously if we have an old kart, there may be the risk that now there might be the request to mount one directly from the person who runs the circuit.
Engineering continues to evolve, but one thing seems to remain the same when we talk about getting our kart out after a winter break or after a long break: it is important to check the brakes. This isn’t just a priority for safety reasons: almost guaranteed that we will have a pedal that goes right down without any resistance whatsoever, with the hydraulic resistance full of air and oil leaks from the rubber washers. Something practically inevitable on a kart that doesn’t have anodised bake components or with automatic recovery, but often also in these other cases, and that is very difficult: in the meanwhile, as it can make someone who takes great care of his kart waste half a day, to make brakes work well by changing washers and anything else , perhaps making him miss out on a driving session; and then in the third millennium it seems to be unacceptable, especially on karts with what they cost today and all the “technology” that everyone talks about in the karting world. If when we take our motorbike out after the winter months we don’t have to put in a new braking system I don’t see why it shouldn’t be the same with a kart too. 
Apart from this, we can give a few other minor operations to “freshen up” our brakes. Besides changing the oil no matter what other problems there may be, we suggest you clean the pads and brake discs with sand paper, so as to remove the superficial patina of oxide and the more solid dirt. You can also remove grease from the braking surfaces with the help of a rag soaked in solvent or trichlorethylene.  

Secondly, let’s consider the engine. To face the winter break we have had to drain the cooling water out. So now the time has come to put some water back into the cooling system (we suggest you use demineralized water that you can buy from any supermarket) taking advantage immediately, before going to the track, to see if there are any leaks from the pump or any other places. In this case too, it is better to take your time before it is too late, that is, be careful because the risk before going to the track is to suffer mechanical problems because the level of the water has dropped too much while lapping.  
Furthermore, remember to warm up the engine before to the track, something that especially on these first visits to the circuit it certainly won’t do any harm and it enables you to see if everything works properly, and to shut the radiator properly. Excessive cooling can cause the same damage as excessive heat, so the system must be adjusted properly: usually it is enough to cover the radiant surface (even normal adhesive tape will do, if we are not racing) but in extreme cases we might have to “protect” the cylinder too. And obviously we suggest using a thermostatic valve.  
Be careful because the fact of using an air-cooled engine doesn’t mean that you are not prone to these difficulties, on the contrary. Also with these engines excessive cooling is deleterious, therefore when the temperature is below 10° it is better to cover the front fins with an “American” adhesive tape. A more elegant solution is to put parts of a petrol pipe between the fins. To prevent or limit the amount of air passing through.  

The low environmental temperature influences the kart not just the engine, but from all other points of view, so it is better to keep our wits about us. For example, it increases the difficulty of even the simplest thing like how to prepare the fuel mixture: with the cold, oil reduces its miscibility, and it is better to mix it very well with the petrol, taking the advantage, if possible, to leave the fuel tank in a warm place (but not near a heater!).
We all know that the tyres are one of the things that suffer most over the cold winter months: if we can’t bring them to the right temperature, the kart is impossible to drive. And the worst situation if we are using second hand tyres that have “rested” throughout winter. The least we can do is take them to a higher pressure, one or two notches higher to contrast the colder air inside while working. Obviously, this variation becomes more or less consistent depending on the environmental situation. When it is really cold, it will help to increase tyre pressure considerably, even up to nearly 2 bar: this because it reduces the surface of the tread that touches the ground, but at least that part which “works” does manage to warm up. For this very reason, it may be a good thing to increase camber too.  

Naturally in this situation you cannot think of using the same set up that offers best results in summer or spring. Don’t forget that, even if we could give a general analysis, each change must however be tried and tested on your own kart, to check that it does actually give the expected results or not: each kart can react differently, besides in extreme environmental conditions, you may find that the kart with a certain set up might react totally different to what we are used to. So, if any change has been made, it is important to check out kart behaviour on the track. Above all, it should always be done this way, testing adjustments that aren’t always logical, because this will help us to improve our knowledge of kart response.  
Usually it is better to get a set up that has more “load" on external wheels: consequently they prefer to increase front height and rear height. Not necessarily front height because we might prefer to increase a bit with caster to help internal rear wheel lift, otherwise even less than what it is with the track in ideal conditions. The different and minor stress also influence the way the body works too. Therefore, we should work on the front supplementary bars, here too, always testing though; tighten or loosen the other elements, such as seat support or bumper support, results can be improved. Also fixing the third bearing axle, if before it was loosened, it may give more traction. To conclude we might have to, in this case reasonably so, change the axle or, if not the hubs; remember that also in this case theory says that the required grip must be sought with “harder” axles, but sometimes we can get better results by working in the opposite direction. So, this brings us to the usual conclusion: it’s ok to trust advice given by the more experienced drivers, but everything must be checked on the track with our own kart and our drive style.

Created by: www.vroomkart.it - 02/03/11

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