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OKN-Junior^[a] (OKN-J) is akart racing class sanctioned by theCIK-FIA for drivers aged 12 to 14. Debuting ininternational competition in 2023,OKN-J is the secondary juniordirect-drive class inFIA championships.

Approved by theFIA World Motor Sport Council in 2022,OKN-J was designed as a simplified version ofOK-Junior regulations to reducecosts for competitors. The class debuted in international competition the following year, being contested in several championships acrossEurope and theMiddle East.

Its inauguralWorld Cup is due to be held in 2025—with qualifying decided vianational championships held in various countries. TheArrive & Drive World Cup is also set to host its first edition in 2025, using a modified OKN-J engine in asingle-design format.

TheCommission Internationale de Karting (CIK-FIA) was founded in 1962 as a sistercommission to theCSI, later known asFISA and theFIA, to govern internationalkart racing competition.^[1] It hosted the firstCIK-FIA World Championship in 1964, which has been held annually since.^[2] TheCIK-FIA began itshomologation of distinct classes in the discipline in 1974, when the first 125 ccgearbox category was created for theEuropean Championship:Formula C (FC).^[3] The 100 ccdirect-drive category was clarified in 1976, whenFormula Europe was introduced to control technical evolutions and costs.^[4] The direct-drive classes were adapted in 1981, when the 135 ccFormula K (FK), 100 ccIntercontinental A (ICA), andJunior Intercontinental A (ICA-J) were introduced to the World Championship, European Championship, andWorld Cup, respectively.^[5] Component technical approvals have been mandated by the CIK-FIA since then.^[6] The 250 ccsuperkart category received World Championship–status in 1983, having reached international competition as early as 1976.^[7][4]

Junior direct-drive classes have evolved substantially since 1981.ICA-J was introduced to the European Championship in 1989 and remained at the World Cup until 1996, where notable winners included twoFormula One World Drivers' Champions:Alain Prost (1973) andFernando Alonso (1996).^[3] In 2007, it was replaced by 125 ccKF3 regulations, later known asKF-Junior (KF-J).^[8] The KF era was marked by decreasing entry figures ascosts for competitors spiralled due to the presence of manually-controlled frontbrakes, sophisticatedcable systems, and fragility of components.^[9] It was eventually replaced byOK-Junior (OK-J) in 2016, which—following iterations by theCIK-FIA—offered improved performance, reduced weight, and increased competition by eliminating thecentrifugal clutch, complex cabling, andstarter motor, with later reductions to therev limiter and exhaustvalve; after six years, it was deemed ready to expand intonational championships.^[9][10]

Plans for a new minimal-costdirect-drive category were submitted by theCIK-FIA to theFIA World Motor Sport Council in 2022; they were approved in July, with theCIK-FIA confirming the "OK-N" category would host its inauguralWorld Cup in 2024.^[11] The "N" suffix is an initialism ofNational, reflecting that qualification for the World Cup would be determined vianational events.^[12] Described as a "hybrid" between theOK andOK-Junior categories,OK-Nengines were first tested in the final round of theEuropean Championship that year atFranciacorta.^[13]

OKN-Junior (OKN-J) was unveiled alongside the senior category, utilising a lowerrev limiter to increasereliability and a higher minimum weight to reducecosts and bolster accessibility; additionally,CIK-FIA events were to operate as asingle-manufacturer discipline, with one brand of engine,chassis, and sixoption tyres.^[14]OKN-J uses an identical design to theOK-N engine, with the only technical difference being a 26 mm (1.0 in)flange on theexhaust.^[15]ACI Sport carried out further tests atSarno andCremona, in preparation for both categories' debuts in theItalian Championship, where they would serve as a gateway fromMini Gr.3 to OK.^[16][14]

The class debuted internationally in2023, featuring in theChampions of the Future Academy Program (COTFA),WSK Euro Series, andWSK Final Cup.^[17][18] Its debut was postponed from February to June, removed from theWSK Super Master Series, and had only one entry in theWSK Open Series, whichKartcom opined was "more a casting error than a failure of the new concept".^[18] It featured the following year in both theAndrea Margutti Trophy andTrofeo delle Industrie.^[19] TheRoad to the World Cup, organised byACI Sport, was held at Franciacorta as asupport race to the 2023World Championship and won byJesse Phillips.^[20]

Qualification for the inauguralWorld Cup in 2025 was decided vianational championships in several countries, as well as thepodium of theAfrican Cup, for a total of 72 drivers. EachNational Sporting Authority (ASN) hosting a national championship were given three entries, with the exclusion of allEuropean Championship entrants.^[21] TheArrive & Drive World Cup was inaugurated that year, featuringVortex engines derived fromOKN-J withcentrifugal clutches.^[22] In the Italian Championship, average entry numbers inOK-N andOKN-J increased from 70 in 2023, to 90 in 2024, to 120 in 2025; a record 190 entered the 2025Cremona round in preparation for the World Cup.^[23] With the increased demand from ASNs, the World Cup increased from 72 to 90 drivers.^[24]

There are 16 main technical features of theOKN-J regulations:^[25]

• 125 cc,direct-drive,single-cylinder,two-stroke, mixed-lubrication,reed valve engine;
• Single cooling circuit for thecrankcase,cylinder, andhead;
• Exhaust port with maximum angle of a 194°;
• Combustion chamber with a minimum volume of 10 cc;
• Mandatorydecompression valve;
• Monotype powervalve;
• Maximum lubricant–fuel mixture of 4%;
• 30 mm (1.2 in) floating chambercarburettor or 24 mm (0.94 in) butterfly carburettor, decided by the governingASN;
• Two-duct 23 mm (0.91 in) intake silencer;
• Digital ignition system withrev limiter of 15,000 rpm;
• Monotypeexhaust with 26 mm (1.0 in)flange and silencer;
• Type-219 chains andsprockets;
• Radiator with one cooling circuit;
• 2WP B2 or BRKR single rearbrake withhydraulic control;
• Primetyres, medium gumcompound;
• Minimum weight of 145 kg (320 lb) with driver, 70 kg (150 lb) without.

The sole differences to thetechnical regulations ofOK-N are the 10 kg (22 lb) minimum weight reduction and the exhaustflange.^[25] Engines,chassis, bodywork, brakes, and tyres are subject to the homologation and approval system operated by theCIK-FIA.^[6] Each year, the specific tyres and fuel for use in competition are selected after acall for tenders.^[26] With elimination of theclutch,electric starter,battery, and electrical wiring,TKART described theOKN-J regulations as being "as simple as it gets".^[10]

TheRoad to the World Cup atFranciacorta in 2023 used Group 1 engines and chassis, andVega XH3option tyres.^[27]

Year	Circuit	Engine	Chassis	Tyres	Ref
2025	Cremona	To be determined

TheArrive & Drive World Cup features anarrive-and-drive format usingOKN-J engines fitted with acentrifugal clutch.^[22]

Year	Circuit	Chassis	Engine	Tyres	Ref
2025	LYL International	Kosmic	Vortex	V	[22]

As of 2025, six engines arehomologated for use inOKN-J by theCIK-FIA, manufactured byModena,IAME,Rexon,LKE,Vortex, andTM:^[28]

Applicant	Brand	Model	Homolog No
ASPA Srl	Modena Engines	ME-K	032-EN-17
IAME SpA SU	IAME	Reedster 5	040-EN-66
Karlheinz Hahn	Rexon Motors	Primaballerina	035-EN-17
Lenzokart Srl	LKE	LK2	033-EN-20
OTK Kart Group Srl	Vortex	VTS	012-EN-11
TM Racing SpA	TM Kart	S3-Senior	041-EN-03

• OK – the primary direct-drive class
• OK-Junior – the primary junior direct-drive class
• KZ – the primary gearbox class
• KZ2 – the secondary gearbox class
• KZ2-Masters – the senior gearbox class
• OK-N – the secondary direct-drive class
• 60 Mini – the under-12 direct-drive class
• Superkart – 250 cc gearbox class
• KF1 – the primary direct-drive class from 2007 to 2012

• FIA Karting

• Kart racing classes
• Recurring sporting events established in 2023

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