The kart engine running-in is very important and depending on this operation, there’s the good engine performance and its duration. Fortunately it is very easy to perform.

It’s very important preparing your petroil with an oil percentage bigger than usual. It’s difficult to define a perfect percentage, anyhow you should keep this oil percentage around 7%-7,5%, so you can use it even after the engine running-in; you could finish the day with a “safe” petroil, even if you cannot expect high performances level. It’s also not so easy defining the necessary quantity of petroil for the running-in: we could say the engine running-in lasts half tank, the problem is that not all tanks have the same capacity….so….. We can assume the engine running-in lasts half hour, dividing this time in 3 steps (and adding some minutes to the last one).

After preparing your petroil, remember to keep a carburetion greasier than usual (not too much.. just a bit….). So now you are ready to start the first step/phase; it will last almost 10 minutes.

1ST STEP:

This step is necessary to get the piston used to run inside the cylinder and create the correct connection between these 2 parts. It has to be done in a very easy/slow phase, when the engine doesn’t overcome 7000 rpm. It’s better keeping 6000 rpm (it’s safer). Anyhow you also have to get the engine used not to keep just one pace, so you have to run about 10 minutes, starting from a low n. rpm and then accelerating to 6000, then let it goes down and then again to 6000; during this operation you have to increase the max revolutions but not the minimum ones. Actually start from 3000 to 6000, and then finish from 5000 to 6000 (increasing just a bit the last ones). After this boring 10-minute phase, go out the track, let the engine cool down, so it will be ready for the second step.

2ND STEP:

You have to act almost as you did during the first step (10 minutes), but this time you have to start from a low number of revolutions, going to 7000, then to 8000 and so on to 12000 in last minutes. Obviously accelerating progressively; after this second step go back to the pit and let the engine cool down which will be then ready for the last 10 minutes.

3RD STEP:

This step is variable based on the engine type, but you have to bring the engine itself to be very close (but not to reach) to the max rpm, remember not to reach it and not to keep this max rpm; go very close to it and then loosen it. In conclusion: accelerate from low rpm, go very close to the max and then loosen it; follow this strategy until the end of 10 minutes. The engine running-in is completed.

Over STEP...:

It sounds nice to call it “over step”... You have to reach the max rpm, and keep it for a moment, after some times you have reached it. Anyhow let always the engine rests a moment after every max reached. You can do everything in 5 minutes. This further step is useful when you have engines which could reach and overcome 20.000 rpm, so for the best ones; with the other ones you can reach the max rpm at the end of the third step/phase. Now you completed the engine running-in, but since the engine didn’t run too many Km, it’s better leaving the carburetion barely greasy for some time, and avoid to push the engine too much for some time after the engine running-in.

Since the engine is still new (also at the end of the engine running-in !!!), it’s better performing one of these 2 advices: or not to go very close to the max for too much time (during the hour following the end of the engine running-in), or assemble a sprocket with 2 teeth more than usual ones.