The chain tension affects the OK engine’s performance? - TKART

The chain’s tension does not affect the performance of the single-speed kart engine

TKART Staff

27 May 2018

Is it true that the chain tension does not affect the engine’s performance? The experts in the field provide an answer to the kart drivers’ doubts.

THE TENSION OF THE CHAIN DOES NOT AFFECT THE PERFORMANCE OF THE SINGLE-SPEED KART’S ENGINE

Reply by

Alessio Piccini

Official racer for Tony Kart Racing Team in the KZ2 category.

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If the chain is too tight, it heats up more easily. Consequently, this increases both its wear and that of the sprocket, until it reaches a breaking point. In this way, the reliability is compromised, and the performance is affected as the engine is not “free” to unload its power to the wheel.
The chain must have the right tension while on the track as this can affect the chassis and axle flexibility, modifying the distance between the gearwheel and the sprocket. These factors should be always kept into consideration in the mounting phase of the engine to the chassis.

TO MOUNT THE MAIN BEARINGS, I FIRST NEED TO PUT THEM IN THE FREEZER

Reply by

Paolo Severi

historic engine specialist, with a rich list of achievements. Owner of the engine manufacturing company SGM

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That is very true! This is the only way to mount the main bearings in the engine. In addition to cooling the bearings, it is necessary to heat the crankcase. The reason is simple: bearings and crankcases are manufactured with extremely strict tolerance levels. We, in the assembly line, use large furnaces which heat crankcases to 80 °C, while we cool the bearings with nitrogen. In this way, exploiting the metals properties of expanding (with extreme heat) and shrinking (with intense cooling) depending on the temperature, we are able to easily insert the bearings, even using hands and without unnecessary exertion. The enthusiasts, who do not have furnaces and nitrogen, have to make due utilizing the freezer (the refrigerator is not sufficient as it does not generate a proper cooling temperature) and a hair dryer. There are no other great alternatives if one wants to implement these processes. One needs to make do with what one has available…

ONE ALWAYS NEEDS TO PUT THE CAPS ON THE TIRES’ VALVES

Reply by

Stefano Mantese

Owner, with his brother Paolo, and Races Director of Vega, leading manufacturing company of tires for karting.

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Mounting the small plastic cap on the valves which allows the inflation of the tires is very important. It is not something that makes you go faster, but it ensures proper safety. The real advantage is when you get on the track with very low pressures, on the order of 0,45 bar. Under these conditions, the deformation of the wheel casing is very likely: for example, on an undulating curb, the tire undergoes continuous stresses which generate pressure imbalances inside it, compression and decompression. In this situation, the small valve tends to be sucked in by the decompression, therefore the tire blows air outside, lowering the pressure inside it, with obvious consequences. It is better to mount the valve caps to avoid those types of consequences. Clearly, it is always best to mount them because it is possible that some valves, even newer ones, may be slightly defective, therefore the tire could deflate by slowly losing internal pressure.