Under Review | ME-K and ME-KJ: Modena Engine’s debut in non-shifter kart engines

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ME-K, ME-KJ: THE FIRST "OK" BY MODENA ENGINES

Carlo Forni

17 January 2019

TYPE
Like most kart engines on the market. 4-stroke engines are still a small niche

125 cc

DISPLACEMENT
125 cc has been the standard for some time now, while in the past it used to be 100 cc

PUSH

START
Push-mode made easy thanks to a decompression valve on the cylinder head that helps the piston

DIRECT DRIVE

GEARBOX
The following are the “families” of kart engines: gears and single speed. ME-K and ME-KJ are single speed clutchless engines

OK / OKJ

HOMOLOGATION
It is the OK non-shifter engines homologation, that at the second one of their history, after their debut in 2016.

After years of production and development of the KZ engine with excellent growth results, Modena Engines relaunches its commitment in the karting field by expanding its range, for the first time, into the OK and OKJ categories with the two new ME-K and ME-KJ engines, presented for the 2019-2021 homologation seasons. .

A well thought out choice, carried forward without proposing revolutionary changes, but rather with the desire to perform extremely well in these categories. Visually, the engines are very similar in their appearance, compact, with an accentuated external profile and, as required, with an external water pump. Internally, there is no shortage of differences, both required by the regulations (presence or the absence of the exhaust valve…), and by precise technical choices.

Beginning from the analysis of the air-intake duct, the two ME-K and ME-KJ engines present a horizontal and classic reed valve pack, with a passage section which, by regulations, in the OKJ model is reduced in size compared to the OK. The conveyor is made of carbon fiber reinforced with Nylon, a material which guarantees the maximum resistance to chemical agents and higher temperatures thus limiting the amount of deformations and expansions.
The entire process is executed very quickly, during the prototyping phase, thanks to the 3D printer, a technology widely used by Modena Engines and for the manufacturing of transfer and exhaust ducts.

Some views of the ME-K engines, on the left, and of the ME-KJ

The different length of the engine reed valve pack (ME-KJ and the ME-K, on the left)

The crankcase is entirely machined in-house, internally, done by using CNC machines

Two surfaces close the lower part of the duct as much as possible, isolating the flow of the blend incoming from the crankshaft and the fly-wheel which create turbulence

The only unrestricted parameters with respect to the regulations, for the power valve featured on the OK engine, are the 3 profile curvatures

A gasket seals the contact point of the valve casing with the cylinder

The 3D printer, widely used by Modena Engines, during the prototyping phase

The reed valves are made of carbon, mounted on 4 passages of equal size for the OK and the OKJ. The difference between the two engines is the thickness of the reed valve pack, with the aluminum duct which connects the carburetor to the reed valve pack, which is a couple of millimeters longer on the OKJ. A device that serves to provide greater response at lower and medium RPMs. Continuing inside the crankcase, one notices how the entire intake duct is carefully machined with CNC machines.