Choose the language.
TKART magazine Must Have | Choose the best transmission system for the kart's water pump
Exclusive Content


Jacopo Colombo
25 November 2023 • 4 min. read

In the cooling system of a 2-stroke kart engine (to find out more, read "Technical | Cylinder cooling" and "Technical | The radiator"), the water pump transmission system plays a key role, when it’s not "embedded", meaning it’s not incorporated into the engine itself, but is external. Its task is to connect the axle to the pump, both of which are equipped with the appropriate pulleys (we analyzed some of them in "Must Have | 5 pulleys on the axle for the transmission of the kart's water pump"). IIn doing so, in fact, the former transfers its motion to the latter which, in turn, pushes the water to circulate in the cooling system. While the resulting end benefit is clear and immediate (keeping the engine temperature within the ideal range, around 50° C, so that it can guarantee optimal performance), the disadvantage that this transmission system entails must also be considered and is the inevitable absorption of engine power which, instead of being directed to the wheels, is "spent" to activate the pump and the cooling system. That’s the reason (as well as others that we’ll see later in this article), over the years, various transmission systems between the axle and water pump have been developed, each with its own peculiarities, its own pros and its own cons. We’ve analyzed the main ones, from the most common to the most "sought after".

N.B. Do you think there are other products that can be added to this selection? Don't hesitate to share them with other TKART users in the "Contributions" section at the end of the article. The community will be grateful to you!



This is the most common transmission belt on the karting scene, especially at an amateur level. There are mainly two reasons: ease of availability and extremely low costs. However, since it’s not a real transmission belt, it has a few defects that are quite significant. One stands out, which is its fragility. Since it’s a product made of NBR (i.e. nitrile rubber), if left unused for any length of time, it tends to dry out and crack, particularly if left exposed to sunlight. This condition is extremely negative because, in the event of breakage, it would interrupt the transmission between the axle and the water pump, blocking its function and causing the cylinder to overheat. Furthermore, in the event of breakage, it’s necessary to remove the axle to repair the transmission with a new O-Ring, which is neither quick nor immediate.

Indicative price

About 2 euro 

To buy:
©Photo: Galiffa Kart

Continue reading the article by subscribing for only 0.96 € / week
Explore these and many other
premium contents
Go to Magazine