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'17 LATEST FOR THE MODENA ENGINES KZ

Carlo Forni

12 May 2017

TYPE
2-stroke engine, like the vast majority of kart engines. 4-stroke is a small niche.

125 CC

DISPLACEMENT
125 cc has become the standard displacement. 100 cc engines are a thing of the past.

PUSH START

STARTER
Starting is the same as always, the push start, with the clutch being released by hand in second gear.

GEARBOX

TRANSMISSION
Two “large families” of engines for karts: single speed and gears. The KZ is a 6-speed unit.

APPROVAL
The approval is for the KZ with gears, renewed this year and valid for 9 years starting from 2016

Approved in 2016, the MKZ 37/M/24 engine manufactured by Modena Engines has been renewed in relation to several essential components. The goal: to make a product that will now be easier to manage by those involved in Karting

The Modena Engines MKZ 37/M/24 engine was approved in 2016. In accordance with the regulations, approval is valid for 9 years, but in this period of time, modifications can still be made: regarding aspects that do not touch the parameters fixed by the approval, or by working on components and measures previously identified in the approval phase.

Updates made by Modena Engines on its KZ engine range from carburetion to setting of timing angles and are really interesting to see in more detail. The stated goal of the changes is to make the management and preparation of the engine easier for clients, or by all those who are not part of official teams who can rely on the direct support of the company or, in any case, professional mechanical experts.

Starting with the suction duct, the first important change is the conformation of the inlet duct in the crankcase, which previously had the geometries of the sloping side walls in the lower and upper sections to accommodate the V-Flow reed valve pack.

This item is not currently being used, since it still requires work to get proper tuning, and has come back to a traditional reed valve pack. Consequently, the geometry of the duct has also been modified.

The MKZ is the Modena Engines engine for the KZ category. Approved in 2016, it immediately distinguished itself because of the project’s many innovative ideas. The 2017 version is a further evolution that continues on this path.

The new cylinder (photo above on the right, and photo below) compared to the old (above, on the left). Note the elimination of the copper anti-detonation ring

The old cylinder head (below) compared to the new one (above), in which there is a cylindrical part a few mm thick that is inserted into the cylinder. In this way, simple copper washers are used to adjust the squish and combustion chamber volume

In the new cylinder (above), the lateral transfer ducts have also been modified, with a wall separating the two ducts, which now begins further inside the ducts

Continuing with the crankcase, in the area above the flywheel and under the lateral ducts, you can see that the lower surface that connects with the lateral ducts is lowered. The profile has a slightly concave pattern with a slight cusp, expertly rounded, before sloping significantly more than the previous version, thereby bettering the flow in the lateral conveyors. In general, the inlet duct increases the width, while the new configuration slightly increases the volume of the crankshaft which, on the one hand, imperceptibly loses some efficiency, and on the other hand it makes carburetion much simpler, thanks to an engine that is not too sensitive to small adjustments, but which performs well even with incomplete carburetion.