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Class Legality

IHRA · ski

Ski GP3

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

  • 2Not legal
  • 2OEM part required
  • 33Not permitted, not listed in the rules
  • 33Legal, with conditions
  • 8Legal

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
Kawasaki 750SX, 750SXI and 750SXI Pro, Kawasaki SXR800, and the Yamaha SuperJet in both its two-stroke and four-stroke forms. No model-year list is published.
Displacement limit
850cc two-stroke and 1050cc four-stroke (M.1). M.2.4 permits the engine to be bored but not past the class limit, and says that where applicable this may exceed the 1 mm overbore of the General Equipment Standards.
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 (3)

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.

  • M.2.4 permits boring "to the class cc limit, which may exceed the 1mm overbore as defined in the General Equipment Standards". There is no section called General Equipment Standards anywhere in this rulebook. The only explicit 1 mm overbore cap is in Sport Spec at U.2.1, which does not govern here.
  • Drop-down domes are prohibited on the Kawasaki heads at M.6.1.1 and the minimum dome volume is given as 28cc. Whether that minimum applies to the 750 and the 800 alike is not separated in the text.
  • The Yamaha SuperJet four-stroke may not use Wedge Sponsons (M.6.2.2). The rulebook names a product and defines nothing, so which sponsons that prohibition reaches is not answerable from this document.

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 reed valve article, in a class built around two-stroke machines. Under the closed-list principle an aftermarket reed cage is therefore not permitted, which is a reading of silence.
  • No sponson article beyond the general J.16 rule and one model-specific prohibition.

What the rules say (78 parts)

8 permitted outright, 33 permitted with stated conditions, 2 refused by a rule we can quote, 2 held to the original part by a rule we can quote and 33 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

Not legal1 part

Aftermarket hoods are not allowed in Ski GP3. M.2.3

OEM part required1 part

The original carburetor body must stay, with only the jets, needle valves and needle valve springs replaceable, the choke removable if it creates no extra air intake, and an aftermarket primer allowed. M.2.2

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 rules31 parts

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

Not permitted, not listed in the rules1 part

The class exhaust rule opens only the hose between the waterbox and the outlet on four-strokes (M.4.2) and a stinger reducer and water fitting on two-strokes (M.4.1); the outlet itself is not listed, and under J.1 and A.2.2 a modification not listed is not permitted. M.4.2

Not permitted, not listed in the rules1 part

No aftermarket hull is listed for Ski GP3, and on a closed list an unlisted modification is not permitted. The SuperJet two-stroke extension is answered under hull extension. A.2.2, J.1

Legal, with conditions1 part

An aftermarket pipe enters Ski GP3 through the model clauses, not the exhaust rule: the Kawasaki SX-R 800 may run an aftermarket wet pipe (M.6.1.4), and a Yamaha SuperJet on the 701 cylinder may run a manufactured, designed and sold wet pipe that functions as one, a dry pipe converted being barred (M.6.2.1.2); on the 760 cylinder the exhaust must remain stock. Other machines and any dry pipe stay at M.4.1, stock pipe plus the reducer and fitting. M.6.1.4, M.6.2.1.2

Legal, with conditions1 part

Only two machines may run one. The Kawasaki SX-R 800 may fit an aftermarket wet pipe (M.6.1.4). A two-stroke SuperJet on the 701 cylinder may fit a pipe manufactured, designed and sold as a wet pipe, never a converted dry pipe, with the CDI kept OEM (M.6.2.1.2). The 750 SX models, a SuperJet on the 760 cylinder and the four-stroke SuperJet keep the stock exhaust. M.6.1.4, M.6.2.1.2

Legal, with conditions1 part

Model-dependent. M.6.1.4 opens an aftermarket wet pipe exhaust system on the Kawasaki SXR800, which reaches its head pipe and manifold. Whether a 701 SuperJet's wet pipe under M.6.2.1.2 may bring its own head pipe is not stated, and every other two-stroke keeps the stock pipe with only a stinger reducer and water fitting (M.4.1), while a four-stroke SuperJet may change only the hose from water box to outlet (M.4.2). M.4.1, M.4.2, M.6.1.4, M.6.2.1.2

Legal, with conditions1 part

Model-dependent. The Kawasaki SXR800 may fit an aftermarket wet pipe exhaust system under M.6.1.4, and the water box, the muffler of a two-stroke wet exhaust, is read as part of that system. Every other Ski GP3 model may only repair its water box, keeping the original internal configuration. M.4.3, M.6.1.4

Legal, with conditions1 part

Only the jets, needle valves and needle valve springs replaceable, the choke removable if it creates no extra air intake, and an aftermarket primer allowed, and nothing else on the carburetor may be changed. M.2.2

Legal, with conditions1 part

An aftermarket flame arrester is allowed if it meets USCG, UL-1111 or SAE J-1928 Marine standards. M.2.2

Legal, with conditions1 part

ECU/CDI may be modified or aftermarket and may carry a programming port, with no additional inputs, outputs or sensors, and a replacement unit uses the original factory connections (M.5). A Yamaha SuperJet on the 701 cylinder must keep the OEM CDI and CDI box; on the 760 cylinder an aftermarket CDI box is allowed (M.6.2.1.2). M.5, M.6.2.1.2

Legal, with conditions1 part

On the Kawasaki 750SX, 750SXI, 750SXI Pro and SXR800 the trigger plate holes may be modified or a timing advance plate added, for advancing only. M.6.1.2

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

J.7, in the general rules for every class, names wiring as replaceable with aftermarket options, which overrides the closed-list default and covers replacement wiring. Connectors are not named on their own, and J.7 does not open added inputs or outputs, a different harness design or an ECU. J.7

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

2-stroke cylinders interchangeable within the same manufacturer. May be bored to the class cc limit, which may exceed a 1 mm overbore. M.2.4 Yamaha SuperJet (2-stroke): 760 cylinder: allowed, aftermarket CDI box allowed, exhaust must remain stock. 701 cylinder: purpose-built wet pipe allowed (converting a dry pipe is NOT), CDI must remain OEM, timing may not be altered, head and base gasket OEM thickness, cylinders OEM bored max 1 mm over. M.6.2.1.2

Legal, with conditions1 part

2-stroke: cooling holes may be modified or removed; not less than 0.05 mm of OEM. 4-stroke: OEM thickness and dimensions +/-10%. M.2.1

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

Kawasaki 750SX, Kawasaki SXR800: Nozzle may be bored. Pump stuffers may be added. M.6.1.3 Yamaha SuperJet (2-stroke): Nozzle may be modified for angle adjustment. M.6.2.1.3

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

The J.16 envelope applies here as it does everywhere else, and section M adds one model exception. Yamaha SuperJet four-strokes may not use Wedge Sponsons. J.16, M.6.2.2

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

Constant mass, not liquid, in normally exposed hull areas. M.4.4

Legal, with conditions1 part

2-stroke: max 2 cylinder-head cooling outlets, no larger than 1/8 inch NPT. No additional fittings. Head must remain stock OEM with no modifications. 4-stroke (M.3.2): waterlines and fittings aftermarket only at OEM size. M.3.1

Legal, with conditions1 part

Yamaha SuperJet two-strokes only, as M.6.2.1.1 allows: the extension may be no wider than the hull's planing surface, may reach no more than 100 mm (3.94 in) beyond the end of the original planing surface, and may carry no hazardous skeg, rudder or fin. Every other eligible model has no extension allowance on this closed list. M.6.2.1.1, A.2.2, J.1

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, M, 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

  • Aftermarket expansion chamber / tuned pipe (2-stroke). Corrected 2026-09-30: this cell cited M.4.1 alone, which allows only a stinger reducer and a water fitting on the stock pipe, the same allowance Ski Lites carries under O.2.5, so the two classes read opposite verdicts from one rule.
  • Footholds, foot straps and tray mats. Corrected 2026-10-02: the Ski GP3 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 GP3 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.
  • Relocated or aftermarket through-hull outlet. Corrected 2026-09-30, Ski GP3: the cell had been graded from a note about the hose and the stinger.
  • Water-injected (wet) exhaust pipe. Corrected 2026-10-02: this row said plain legal from the SX-R 800 clause alone. The class allows a wet pipe on two machines only, and the SuperJet one with conditions.
Cite this page

“Ski GP3, IHRA class rules”, BaddJet archive, https://baddjetarchive.com/legality/ihra/ski-gp3/

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78 parts read · 8 permitted, 33 with conditions · 2026 rulebook

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