OK-N

OK-National (OK-N) is an international kart racing class sanctioned by the Commission Internationale de Karting (CIK-FIA) for drivers aged 14 and over. Debuting in international competition in 2023, OK-N is the secondary senior class in FIA championships to OK.

Approved by the FIA World Motor Sport Council in 2022, OK-N was designed as a simplified version of OK regulations to reduce costs for competitors. The class debuted in international competition the following year, being contested in several championships across Europe and the Middle East.

Its inaugural World Cup was held in 2024—with qualifying decided via national championships held in 12 countries—and won by Kyuho Lee. The Arrive & Drive World Cup hosted its first edition in 2025, using a modified OK-N engine in a single-design format.

The Commission Internationale de Karting (CIK-FIA) was founded in 1962 as a sister commission to the CSI, later known as FISA and the FIA, to govern international kart racing competitions. It hosted the first CIK-FIA World Championship in 1964, which has been held annually since. The CIK-FIA began its homologation of distinct classes in the discipline in 1974, when the first 125 cc gearbox category was created for the European Championship: Formula C (FC). The 100 cc category was homologated in 1976, when Formula Europe was introduced to control technical evolutions and costs. The direct-drive classes were adapted in 1981, when the 135 cc Formula K (FK), 100 cc Intercontinental A (ICA), and Junior Intercontinental A (ICA-J) were introduced to the World Championship, European Championship, and World Cup, respectively. Component technical approvals have been mandated by the CIK-FIA since then. The 250 cc superkart category received World Championship–status in 1983, having reached international competition as early as 1976.

Senior classes have evolved substantially since 1981. Formula Super 100, later known as Formula A (FA), was introduced in 1988 as an additional World Championship class to FK, which was replaced by Formula Super A (FSA) in 1993. FSA was disbanded after 2002 and was followed by FA and ICA in 2007, when 125 cc KF1 and KF2 regulations were introduced. The KF era was marked by decreasing entry figures as costs for competitors spiralled due to the presence of manually-controlled front brakes, sophisticated cable systems, and fragility of components. It was eventually replaced by Original Kart (OK) in 2016, which—following iterations by the CIK-FIA—offered improved performance, reduced weight, and increased competition by eliminating the centrifugal clutch, complex cabling, and starter motor, with later reductions to the rev limiter and exhaust valve; after six years, it was deemed ready to expand into national championships.

The OK-N concept was approved by the FIA World Motor Sport Council in 2022.

Plans for a new minimal-cost direct-drive category were submitted by the CIK-FIA to the FIA World Motor Sport Council in 2022; they were approved in July, with the CIK-FIA confirming the "OK-N" category would host its inaugural World Cup in 2024. The "N" suffix is an initialism of National, reflecting that qualification for the World Cup would be determined via national events. Described as a "hybrid" between the OK and OK-Junior categories, OK-N engines were first tested in the final round of the European Championship that year at Franciacorta.

OK-N was unveiled alongside its junior category, OKN-Junior, utilising a lower rev limiter to increase reliability and a higher minimum weight to reduce costs and bolster accessibility; additionally, CIK-FIA events were planned to operate as a single-manufacturer discipline, with one brand of engine, chassis, and six option tyres. ACI Sport carried out further tests at Sarno and Cremona, in preparation for both categories' debuts in the Italian Championship, where they would serve as a gateway from the under-12 Mini Gr.3 class to OK.

The class debuted internationally in 2023, featuring in the Champions of the Future Academy Program (COTFA), the WSK Euro Series, and the WSK Final Cup. Its debut was postponed from February to June, removed from the WSK Super Master Series, and had only one entry in the WSK Open Series, which Kartcom opined was "more a casting error than a failure of the new concept". The COTFA was won by Luna Fluxá the following year, who became the fifth woman in history to win a major senior international karting title, and the first in a global championship since Susanna Raganelli in 1966. It featured that year as the primary senior class in the Andrea Margutti Trophy and Trofeo delle Industrie. The Road to the World Cup, organised by ACI Sport, was held at Franciacorta as a support race to the 2023 World Championship and was won by Antonio Apicella. In addition to the this event—where the top-three were awarded places at the World Cup—qualification was decided via national championships in 12 countries, as well as the podium of the African Cup, for a total of 36 drivers.

The inaugural OK-N World Cup was held at PF International in 2024.

The inaugural World Cup was held at PF International and won by South Korean driver Kyuho Lee in wet conditions. Entries to the World Cup were initially tightened for 2025, with each National Sporting Authority (ASN) hosting a national championship given three entries and the exclusion of all European Championship entrants. The Arrive & Drive World Cup was inaugurated that year at LYL International in Malaysia, featuring Vortex engines derived from OK-N with centrifugal clutches, and was won by Zach Tucker of New Zealand against 58 competitors from 30 nations. In the Italian Championship, average entry numbers in OK-N and OKN-J increased from 70 in 2023, to 90 in 2024, to 120 in 2025; a record 190 entered the 2025 Cremona round in preparation for the World Cup. With the increased demand from ASNs, the World Cup increased from the planned 72 drivers to 90 and was dominated by Italy's Manuel Scognamiglio.

In 2026, OK-N is set to be contested at three national championships within the COTFA framework in Macau, the United Arab Emirates, and the United Kingdom. As part of the FIA's phased "Global Karting Plan", the arrive-and-drive concept is set to expand to European and Asia-Pacific Championships.

There are 16 main technical features of the OK-N regulations:

• 125 cc, direct-drive, single-cylinder, two-stroke, mixed-lubrication, reed valve engine;
• Single cooling circuit for the crankcase, cylinder, and head;
• Exhaust port with a maximum angle of 194°;
• Combustion chamber with a minimum volume of 10 cc;
• Mandatory decompression valve;
• Monotype power valve;
• Maximum lubricant–fuel mixture of 4%;
• 30 mm (1.2 in) floating chamber carburettor or 24 mm (0.94 in) butterfly carburettor, decided by the governing ASN;
• Two-duct 23 mm (0.91 in) intake silencer;
• Digital ignition system with rev limiter of 15,000 rpm;
• Monotype exhaust with silencer;
• Type-219 chains and sprockets;
• Radiator with one cooling circuit;
• 2WP B2 or BRKR single rear brake with hydraulic control;
• Prime tyres, medium gum compound;
• Minimum weight of 155 kg (342 lb) with driver, 70 kg (150 lb) without.

Engines, chassis, bodywork, brakes, and tyres are subject to the homologation and approval system operated by the CIK-FIA. Each year, the specific tyres and fuel for use in competition are selected after a call for tenders. With elimination of the clutch, electric starter, battery, and electrical wiring, TKART described the OK-N regulations as being "as simple as it gets". Competitors are mandated to hold either an F-grade or an E-grade International Karting Licence issued by their ASN, requiring drivers to be aged 14 or over.

The Arrive & Drive World Cup features an arrive-and-drive format using OK-N engines fitted with a centrifugal clutch.

As of 2025, six engines are homologated for use in OK-N by the CIK-FIA, manufactured by Modena, IAME, Rexon, LKE, Vortex, and TM:

• OK – the primary senior class

• OK-Junior – the primary junior class

• KZ – the primary gearbox class

• KZ2 – the secondary gearbox class

• KZ2-Masters – the senior gearbox class

• OKN-Junior – the secondary junior class

• 60 Mini – the under-12 class

• Superkart – 250 cc gearbox class

• KF1 – the primary senior class from 2007 to 2012

• FIA Karting