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Class Legality

IHRA · ski

Ski GP2

IHRA 2026, L. A closed-list class. The craft must stay stock except where the rules allow otherwise, so anything unlisted is not permitted.

  • 1Not legal
  • 7OEM part required
  • 30Not permitted, not listed in the rules
  • 23Legal, with conditions
  • 7Legal

Read out of the published IHRA rulebook on 2026-09-11, so confirm anything that decides a purchase. The full note is at the foot of the page.

Running the class

Eligible craft
Exclusively the Kawasaki SX-R 1500. No model-year list is published.
Displacement limit
1500cc (L.1). L.2.1 permits the engine to be bored and does not repeat the figure. L.1 states it of the watercraft competing, so a craft bored past it stops meeting the class criteria.
Licence or tier
Not stated.
Minimum weight
Not stated.

Read from the same class section as the part answers. The rider side of the sport, tiers, ages, licences and what gets inspected, is set out across the bodies at Racing.

Open questions on this class (1)

Places where the rulebook contradicts itself, or where a figure could not be settled. Nothing in this list is decided, and it sits here rather than in a footnote because it is what you would want before spending money.

  • The L.2.6 head gasket rule is internally contradictory. It requires a gasket no thinner than "0.005 mm (0.002 in)" than OEM and then permits between 0.005mm and 1.55mm thicker, and the conversion is wrong in the source, since 0.002 in is about 0.0508 mm. No numeric gasket tolerance is publishable for this class.

Sections this rulebook does not contain for this class

Confirmed absent by a targeted read rather than merely unnoticed. In a closed-list class an absent article is why a part reads as not permitted; in an open class it is why one reads as open.

  • No hull-substitution rule. The hull article, L.5, covers only ventilation and the hood. Under the closed-list principle at A.2.2 and J.1 an aftermarket hull is therefore not permitted here, which is a reading of silence rather than a quoted prohibition.
  • No forced induction article, in a class whose single eligible craft is naturally aspirated.

What the rules say (68 parts)

7 permitted outright, 23 permitted with stated conditions, 1 refused by a rule we can quote, 7 held to the original part by a rule we can quote and 30 refused by our reading of the class rather than by a quoted rule. Grouped where the same rule gives the same answer, so two "Not legal" groups can sit side by side under different rules.

What each answer below means

Not legal
This comes off. The rules refuse it in this class.
OEM part required
This comes off. Only the part the manufacturer fitted is allowed here.
Not permitted, not listed in the rules
Treat it as coming off. The class requires the craft to stay stock except where the rules allow otherwise, and this part is not on the list, so this is our reading rather than a rule we can quote at you.
Legal, with conditions
Keep it, but measure it: the rules permit this part only inside stated limits.
Legal
Keep it. The rules permit this part in this class.

Read the refusals as a list of work. Anything below marked Not legal, OEM part required, or Not permitted has to come off the machine, or go back to the standard part, before it races in this class.

Not legal1 part

Bolts, nuts and washers may not be substituted with titanium unless originally equipped. Locking mechanisms are allowed. J.7

OEM part required1 part

The original ECU must stay and may only be reprogrammed, on its own inputs, outputs and connectors, with no sensor added, so an aftermarket or standalone box is not legal here. L.4.1

OEM part required1 part

Must remain OEM. Timing adjustable within limits; adjustable timing sprockets permitted. L.2.3

OEM part required1 part

A ski hull may be repaired, or reinforced against course obstacles, but only within 2 mm (0.08 in) of its original configuration, and no other hull work is listed. J.1, J.13

Not permitted, not listed in the rules29 parts

On a closed list an unlisted modification is not permitted. A.2.2, J.1

Not permitted, not listed in the rules1 part

L.2.5 lists no aftermarket manifold or head pipe: the OEM exhaust manifold may be drilled or tapped if the holes are sealed, aftermarket hose or piping is allowed only from the water box to the exhaust outlet, and the water box and manifold outlet may not be modified. A.2.2, J.1, L.2.5

Legal, with conditions1 part

The class requires a flame arrester meeting USCG, UL-1111 or SAE J-1928 rather than the OEM one, so a compliant aftermarket arrester reads as allowed. L.3.1

Legal, with conditions1 part

The ducting between the flame arrester and the throttle body may be modified or aftermarket, or only as far as the airflow sensor where one is fitted, and nothing downstream of the sensor may change. No cold air system is named, so the allowance stops at that ducting. L.3.1

Legal, with conditions1 part

Reprogramming the original unit is the permitted route, on its own inputs, outputs and connectors, with no sensor added. L.4.1

Legal, with conditions1 part

Gauges may be modified or removed provided no hazard is created and any resulting hole is sealed. Section J permits modification and removal and never addresses adding an aftermarket instrument. J.15

Legal, with conditions1 part

Replacement wiring is allowed as a maintenance part under J.7, and L.4.1 keeps the ECU on its original inputs, outputs and connectors; J.7 opens no harness redesign and no ECU. J.7, L.4.1

Legal, with conditions1 part

Must retain the original compression ratio, dome profile, skirt length and material type, and the ports must not be abrasively cleaned, with piston weight within 25 per cent. L.2.1

Legal, with conditions1 part

Repairs are allowed for a crack or puncture, but only one damaged area affecting one cylinder bank. No other modification. J.11

Legal, with conditions1 part

Replacements must match OEM weight and dimensions. L.2.7

Legal, with conditions1 part

May be modified or replaced with an aftermarket part. The original diameter must be maintained in Stock class, and the rulebook never defines which classes that is. J.18.2

Legal, with conditions1 part

May be replaced within OEM specifications. J.18.3

Legal, with conditions1 part

Aftermarket or modified, full-length type with at least one bar parallel to the driveshaft, dropping no more than 12.00mm (0.47 in) below the flat plane of the pump intake. J.18.1

Legal, with conditions1 part

Aftermarket or modified. An extension may not exceed the width of the original plate, and on a ski may not extend more than 100 mm (3.94 in). J.18.1

Legal, with conditions1 part

Replacement trim plates may be used provided they mimic the handling characteristics of the stock plates. J.18.2

Legal, with conditions1 part

Aftermarket, modified, repositioned or removed. Up to two, each no longer than 36 in (91.45 cm), protruding no more than 3.94 in (100 mm) horizontally, at least 6 mm thick with radiused leading edges, and not attached to a planing surface. J.16

Legal, with conditions1 part

Mat kits and padding are allowed in every class by the general rules (J.14), which overrides the closed-list default. Footholds and foot straps are not named there, so they stay not permitted. J.14

Legal, with conditions1 part

The handle pole assembly and mounting brackets may be modified or replaced provided original functionality is retained. Length may be altered and the attaching point reinforced. J.17.2

Legal, with conditions1 part

Replacement bumpers and side rails may be used provided they create no hazard. A permanently affixed nose bumper remains required. J.13, I.17

Legal, with conditions1 part

May be added to adjust handling. Constant mass only, and no other part may be modified to carry it. J.19

Legal, with conditions1 part

No new fittings on the engine block. Existing unused fittings may become water supply lines at unchanged thread diameter, and electronic valves and water injection are prohibited unless OEM. L.2.4

Legal1 part

J.7, in the general rules for every class, names hoses and clamps as replaceable with aftermarket options, which overrides the closed-list default and covers an aftermarket fuel hose. Fittings are not named on their own. J.7

Legal1 part

May be replaced, as may starters and oil injection systems, with the oil injection system removable or disconnectable. J.8

Legal1 part

Grips, throttle and cables may be modified or aftermarket. The bar must be padded at the mounting bracket or the crossbar padded. J.17.1

Legal1 part

Steering shaft, holder, handlebar holder and cables may be aftermarket, and quick-turn modifications are allowed. J.17.2

Legal1 part

The bilge pump may be modified or disconnected and aftermarket bilge draining systems are permitted, provided they create no hazard. J.10

IHRA 2026, L, read from the rulebook on 2026-09-11. Read the rule yourself. Every IHRA class · where the rulebooks differ · how this site reads a rulebook.

This is one class. Every part below also has a page of its own showing where it stands across every class this body runs, and legality by part is the index of them.

What we corrected here, and when

  • Footholds, foot straps and tray mats. Corrected 2026-10-02: the Ski GP2 row read the closed-list default and refused a mat kit, which J.14, in the general rules for all classes, allows.
  • High-pressure fuel line and fittings. Corrected 2026-10-02: the Ski GP2 row read the closed-list default and refused a fuel hose, which J.7 allows in every class; until 2026-10-31 this line wrongly excepted the drag section, where J.7 applies too.
Cite this page

“Ski GP2, IHRA class rules”, BaddJet archive, https://baddjetarchive.com/legality/ihra/ski-gp2/

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68 parts read · 7 permitted, 23 with conditions · 2026 rulebook

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