#TechnicalTuesday - Things to know (part 1)

Written by Maurizio Voltini.
 
Among the various tendencies that karting has been through over the past years, there is also that of direct dialogue among the protagonists that is, talk to other drivers exchanging ideas and information. You see, that when karters talked to each other it wasn’t just a way of passing the time, but it allowed them to learn many things. In a sport like karting where there is a remarkable “change”  (and we aren’t talking about underwear or clothes, nor about spare parts, but about the fact that several drivers take up – and stop – practicing karting each year)  this situation was very favourable for karters who were beginners, those who after having bought a second hand kart (maybe so worn that it didn’t work properly) from someone they knew, they go to the track almost without knowing anything about karting, and sometimes they don’t even know the basics of mechanics. Well, seeing that it has become very difficult to find a track attended by the more expert drivers, those who were usually there before and would give sound advice and warnings to newcomers, here at Vroom we are going to try and give you this advice on what you should do, showing you some minor but important details and things to control and check, operations that are normal for the more experienced drivers, but they are unknown to beginners. All this is to make sure that the first days at the track are days of fun and not disappointment and suffering maybe for not having even been able to start your kart.
 
1)             Not enough to say “tighten”
 


As in any situation where you need to know a bit about mechanics, one of the basic operations is knowing how to tighten nuts and bolts. But besides knowing in what direction they screw up or loosen, it is worthwhile knowing a little bit more. For example, nuts and bolts must not be tightened “to death”: obviously they have to be tight, but don’t exaggerate because you risk ruining the components, especially if they are made of “soft” material like aluminium (talking of this, don’t forget to put some washers in). Things are even different for the wheels: in fact, due to regulation and manufacturing decisions that aren’t well thought out, there is a paradox that the nuts that lock the wheels to the hubs are also the “weaker” ones on the internal part of the kart (when, logically, it should be the other way round). So, you have to be careful not to lock them too tight, and change them without even thinking about it if they do not screw up smoothly. Remember to lock all the nuts progressively (this applies to all similar situations) that is never tighten or unscrew a nut completely or directly, but working on all three contemporarily a bit at a time. In fact, if the circle is locked only on the one side, it could bend or even crack, something to avoid. Oh, one last thing, to prevent surprises: never put in a nut or a screw without tightening them immediately after, there and then. Too many times these come away on the track while you are driving because something has happened and you have “forgotten” to tighten them… 
 
2)             Look after the chain


 
Final drive, in a kart, is quite simple and it really does not require specific engineering knowledge, but obviously this time too, it is good, if not basic, to know a few basic rules. Well, it isn’t sufficient to remember to grease the chain every time that you leave the track (this is the first precaution that not everyone knows when they first take up karting). 
You find specific grease readily available so there is not much more to say on the matter. However, it is very important to know, especially when we take a kart to the track for the first time or if we change an engine, is to align crown and pinion. Usually it is sufficient to loosen the crown holder from the axle side and putting it in the right position with the help of a straight “set square” (you could use the blade of a small saw), also check (and while we are about it) make sure that the crown is not undulated. Then adjust the tension of the chain, it must be neither too lose nor to tight: on average it is ok for the free part of the chain to oscillate by about a centimetre. To do this always tighten the front U-bolt before the rear one. Also check it by making the wheels turn a quarter turn at a time, to see if the tension remains constant, otherwise it means that the crown is not mounted perfectly cantered (or worse still, the axle might be crocked). Last but not least, check the chain to make sure that there are no “gripped” links. One last thing if you haven’t got a chain stretcher – that is just put on the engine and isn’t fixed – check to see that the tension is constant and that the engine hasn’t moved back after hitting the curb.
 
3)             You must have petrol


 
Continuing to work near the engine, after drive we go on to feed: engines work by “taking in” air and petrol; therefore it is important to make sure that these two elements get there. In particular as far as fuel is concerned: if u haven’t used your kart for a while – not to mention if you haven’t checked the mechanical parts – it is almost sure that the feed circuit (carburettor, pump, pipes, etc.) is full of air. To solve this problem, all that you have o do is let the engine turn freely (that is, without the spark plug) or also by rocking it backwards and forward, keeping your hand on the induction: the depression that forms automatically draws petrol (that is if there is some in the hand directly on the carburettor: This way you will feel when the petrol has actually arrived, tank…). This operation is commonly known a “calling the fuel”. It is better to “cover” with your without running the risk of getting the filter box full if there should be more petrol than necessary. 
 
4)             Also the spark…

 

Like petrol, fundamental for an engine to work the spark is just as important for it to ignite. All operations concerning chain maintenance and filling the feed system, as we have said, are nearly always carried out with the spark plug off to let the engine turn freely. Well, this operation allows us to check directly and easily that the ignition works too.  In the meanwhile, don’t forget that every time that you let the engine turn like this, it is better to put the spark plug in the pipette and in contact with the metal area of the engine (so as to make “mass”) so that the current that is produced in the bobbin can download regularly (the risk is that the same bobbin head might get bored: do you want to put it right?).  This way, we can see with our own eyes if the spark does really occur between the electrodes of the spark plug and not in other areas (in which case, it is better to put another spark plug in). In the same way, if the engine doesn’t manage to start, we can check if the spark is right, but also if it is wet (too much petrol or doesn’t ignite) or dry (the petrol doesn’t get there).