2020 H²O Super Libre Series Technical Regulations

(Within Motorsport UK- Formula Libre Class Regulation)

IAME Lynx, Maxi, Leopard, & X30 Engines


Introduction. This class endeavours to provide, at club level, a low maintenance and affordable means of Kart racing for all senior enthusiast regardless of weight.

Why this engine type? The IAME Lynx, Maxi, Leopard & X30 (IAME RL UK TaG range) engines are one of the most user friendly kart engine range ever produced, with long engine life between rebuilds, easy touch start ignition, tuneable carburettor and an alternator to ‘keep the battery charged’ while the engine is in use. The complete engine kit is ‘ready to race’ including engine, radiator, battery, airbox, cdi and all connections and hardware – simply bolt it on and go racing!  There is a good supply of these engines and spares around in UK either used or new. However the X30 engine must be fitted with pre 2017 Ignition, Carb and Exhaust system. The 4 options of engines ensures that the heavier driver can race the lighter driver, a true grass roots clubman class.

These engines are not sealed and is easily maintained by the clubman driver keeping costs down.

All H²O drivers use the Euro style 3 digit race number system


Key features about the class

One class with 4 weights (total kart +driver) one race for all.

Weight Categories (Kart +Driver)

Min driver Weight

IAME RL UK TaG range Engines permitted


No min kg

Lynx Unrestricted 100cc OR X30 Restricted 125 cc (X30 fitted 26mm Ø restricted exhaust manifold part number  X30125366 /01/15 TBC) 



Maxi Unrestricted 115 cc OR X30 Restricted 125 cc (X30 fitted 29mm Ø restricted exhaust manifold part number  X30125366)



Leopard Unrestricted 125 OR X30 125 cc (X30 fitted silver 31mm Ø restricted exhaust manifold part number  X30125367)



X30 Unrestricted 125 cc (exhaust manifold part number X30125365 ) = 190 Kg Driver min 96 kg



The one set of dry tyres per 2 rounds rule helps the driver on a budget and reduces environmental waste.



The class will be incorporate within the Regulation Motorsport UK 2020 Yearbook and Specific regulations for Karting (U) and Motorsport UK and, 2020 Kart Race Yearbook- Formula Libre

Reference: IAME RL UK TaG engine- as used in UK Clubman Class, X30 & Formula Blue

Class: H²O Super Libre Series (IAME Lynx, Maxi, Leopard & X30 (Homologation 05/ENG/14 fitted with Selettra ignition 2013-2015 X30125952-Black coil , Tryton HB 27).


Engine Bore: (mm)

  • Lynx : 50.12-50.90 Ø
  • Maxi : 54.00-54.40 Ø
  • Leopard : 54-54.40 Ø
  • X30: 54-54.40 Ø

Stroke (mm)

  • Lynx : 50.00  
  • Maxi : 52.00 
  • Leopard : 54.00
  • X30: 00


Modifications. The engine /engines must conform to the registered / manufacturers fiche or conform to the original importers specification as lodged and agreed with the Motorsport UK .Its function must remain in the condition as intended and designed. No modification or alterations are permitted except where H²O expressly allowed. Squish gap between combustion chamber and piston is free.

All parts used on or in these engines must be of original manufacture type or source. Fitting of heli-coils and inserts to repair damaged threads is allowed.

Appearance: The engines external appearance must remain as original. 

Cylinder head: Must original colour.

Carburettor: As per class regulations for the engine, or separately approved by the MSA for any type IAME RL UK TaG engine (Including Tillotson HL344, HL360 & pre 2016 X30 Tryton type HB27 / Excluding Tillotson HW27)

Reeds: Any thickness of reeds may be used inc carbon fibre.

Reed block – H²O approved or originally supplied with any type IAME RL UK TaG engine.

Airbox: Any CIK airbox may be used, with a maximum of 2 intake holes, maximum dia 22mm, inc side entry intakes.

Clutch/Drum: The standard clutch/drum to original design must be used with 10T or 11T sprockets

Ignition: Either red/green button control or the ECU key switch type Selettra ignitions may also be used, including  pre 2016  X30 systems (Black coil & ignition, the ignition rotor woodruff key must be installed and as standard timing position and asper the relevant advance curve control listed on homologation). X30 Rotors may be fitted with 10mm ID/12mm OD bushes and key ways accordingly.X30 2016 Selettra digital S- Blue ignitions are not allowed.

Ignition Timing: as factory set.

Wiring Loom: All wires must be connected using the appropriate connectors, and in working order,

Selettra ECU: type A OR type C

Ignition General: The driver must be capable of both starting & stopping the engine using the key switch or control buttons. The battery must be electrically connected as intended to the alternator at all times when engine is running. An external starter may be used in the event of starter motor failure. The key switch, Relay & ECU May be attached anywhere on the Nassau panel, steering wheel, fuel tank stays or with battery on main chassis rail. An original Mitsuba or non-genuine starter motor may be used. 

Note Safety– Key switch operation Blue Arrow, must point to the cut out/key switch to enable turn off an engine in the event of an incident.  Push Button – red stop must be clearly accessible.

Cooling system: The radiator, pump, axle pulley must be as originally supplied with any type IAME RL UK TaG engine, rubber or silicone replacement hoses are allowed. An in-line thermostat/temp sensor may be used, a manually operated radiator blind may be used.

Spark Plug: Spark plug and heat range is free 

Battery: Any 12v sealed lead acid battery OR 14v lithium polymer batteries may be used.

Batteries must be securely attached inside the original IAME battery holder using any fixings/clamps of an appropriate strength and construction, to the left hand main chassis rail. (Either type of IAME battery holder may be used) 

 Exhaust: H²O approved or originally supplied with any type IAME RL UK TaG engine however. Motorsport UK yearbook noise levels apply (U16.16) a silencer end can must be fitted. Exhaust flex length is free. As a commitment to noise reduction, it is mandatory to use effective heatproof webbing or similar sleeve material wrapped around the exhaust flex to help reduce noise. Make is free.

Engine specific scrutineering:  Bore and Stroke.

Chassis:  Any chassis conforming to Motorsport UK Yearbook regulations for non-gearbox karts.

Bodywork: CIK homologated including front dropdown fairing.

Tyres: Tyre Dry: Komet K1H /Vega SL4 (ACR) /Maxxis Sport- Rain: Komet K1W/Vega W5/W6

Note: A driver using a new set of dry tyres will have to use those tyres for their next 2 consecutive rounds raced unless proven unsafe to use. (Barcode Process to apply).  IN THE EVENT OF A WET MEETING WHEN DRY TYRES ARE NOT USED DURING THAT RACE DAY THEN THE DRY TYRE RULE WILL BE CARRIED OVER TO THE NEXT ROUND ENTERED.    


  • 160kg Including driver
  • 170kg Including min driver weight 76kg
  • 180kg Including min driver weight 86kg
  • 190kg Including min driver weight 96kg 

 Numbers: Yellow back ground, Black numbers, (Novice Black background White numbers)

Note a driver may drop down to a smaller engine size (IAME RL UK TaG range) but must remain on the original weight and number category as registered for the event.

Race numbers Allocation: (free choice 2020 on membership)

  • 101- 199 – 160 kg
  • 201 -299 – 170 kg
  • 301- 399 – 180 kg
  • 401- 499 – 190kg

The class is open to any driver aged 16 or over.

H²O Super Libre Series reserves the right to amend the regulations (Carburettor and or Exhaust Restrictors) should the performance require adjustment on safety grounds and to preserve comparable kart performance.

Regulations as of 1st Feb 2020 V2