IHRA · ski
IHRA 2026, P. A closed-list class. The craft must stay stock except where the rules allow otherwise, so anything unlisted is not permitted.
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.
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.
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.
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.
12 permitted outright, 36 permitted with stated conditions, 2 refused by a rule we can quote, 6 held to the original part by a rule we can quote and 22 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.
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
A two-stroke entry may not relocate the exhaust gas exit and must keep its original opening size under P.2.1. A four-stroke entry inherits N.2.5 through P.1, which frees only the piping between the water box and the outlet pipe and never lists the outlet, so a change there is not permitted under the closed list. P.1, N.2.5, P.2.1, J.1
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 water box stays OEM on either engine type: N.2.5 bars any change to it on a four-stroke entry, and P.2.1 frees the two-stroke exhaust only as far as the hose to the OEM water box. N.2.5, P.2.1
OEM part required1 part
The injectors stay as the manufacturer supplied them, because P.1 applies the Four Stroke Ski Lites fuel system rule to four-stroke entries without exception. P.1, N.3.2
OEM part required1 part
The electric pump stays OEM for four-stroke and two-stroke entries alike (N.3.2, O.3.2). The only pump P.2.4 adds is an aftermarket crankcase-pressure pump on a two-stroke entry, with extra pulse line fittings on the crankcase. N.3.2, O.3.2, P.2.4
OEM part required1 part
Only the OEM fuel tank may feed the engine on either engine type, since P.1 and P.2 carry over N.3.2 and O.3.2 and the P.2 additions leave the tank alone. N.3.2, O.3.2
OEM part required1 part
Four-stroke entries keep stock camshafts under P.1, with replacement bearings or shells to the original specification and the cam timing open to adjustment. P.1, N.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 rules21 parts
On a closed list an unlisted modification is not permitted. A.2.2, J.1
Not permitted, not listed in the rules1 part
P.2.2 frees the cylinder head on two-stroke entries only, and a four-stroke entry takes the Four Stroke Ski Lites rules with no exception, which list no head work beyond a one-bank repair that brings no performance gain. P.1, N.2.1, P.2.2, J.1
Legal, with conditions2 parts
Model-dependent. A two-stroke entry may run modified or aftermarket carburetors with no more venturis than cylinders and no slide type, while a four-stroke entry follows Four Stroke Ski Lites, which lists no carburetor change. P.1, P.2.4
Legal, with conditions1 part
Two-stroke entries: Manifold, head pipe, expansion chamber, gaskets, and hose to the OEM water box. Exit location and original opening size must be maintained. P.2.1
Legal, with conditions1 part
Model-dependent. A four-stroke entry keeps its manifold outlet unmodified and may only run aftermarket piping from the water box to the outlet pipe, as Four Stroke Ski Lites allows (P.1, N.2.5). On a two-stroke entry P.2.1 frees the manifold, head pipe, expansion chamber, gaskets and the hose to the OEM water box, with the exhaust exit kept in place and at its original opening size. P.1, N.2.5, P.2.1
Legal, with conditions1 part
Model-dependent. N.3.1 keeps the intake manifold, screens and spark suppressors stock on a four-stroke entry, and P.1 grants no exception, while P.2.4 lets a two-stroke entry run a modified or aftermarket intake manifold assembly. P.1, N.3.1, P.2.4
Legal, with conditions1 part
Model-dependent. Both engine types may run a flame arrester meeting USCG, UL-1111 or SAE J-1928, but a four-stroke entry keeps the intake manifold, screens and spark suppressors stock behind it (N.3.1), while a two-stroke entry may fit an aftermarket arrester (O.3.1) and may also change its carburetors and intake manifold under P.2.4. N.3.1, O.3.1, P.2.4
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. P.1, N.3.1
Legal, with conditions1 part
Model-dependent. Reprogramming is open on a four-stroke entry only within the stock unit's input and output count, with no sensor added (P.1, N.4.1). A two-stroke entry may modify its unit under O.4.1 so long as no sensor is added. N.4.1, O.4.1
Legal, with conditions1 part
Model-dependent. A four-stroke entry must keep the original ECU, which may only be reprogrammed, so a standalone box is not legal on it (P.1, N.4.1). On a two-stroke entry O.4.1 lets the unit be replaced with an aftermarket one provided no sensor is added, and P.2.5 separately opens the CDI. N.4.1, O.4.1, P.2.5
Legal, with conditions1 part
On a two-stroke entry P.2.5 lets the CDI unit be modified or replaced with an aftermarket unit and the RPM limiter be bypassed or removed, while the original charging system must stay, and the Ski Lites rule carried in by P.2 adds that no sensor may be added. O.4.1, P.2.5
Legal, with conditions1 part
P.2.5 permits ignition timing adjustment and modification of the original ignition pickup mount, beyond the trigger-plate slotting and adapter plate of O.4.2, while the original equipment charging system must stay. O.4.2, P.2.5
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
Must fit the original battery box and be securely fastened. J.9
Legal, with conditions1 part
Model-dependent. A four-stroke entry may be bored, with the replacement piston matching the OEM compression ratio, dome profile, skirt length and material (P.1, N.2.1). A two-stroke entry follows O.2.1, which also requires the original port timing and skirt shape, a weight within 25 per cent and port chamfers of no more than 1 mm at 30 degrees, with a non-conforming piston only by written permission. N.2.1, O.2.1
Legal, with conditions1 part
Model-dependent. The crankshaft of a four-stroke entry stays stock apart from bearings or shells of the original type and size (P.1, N.2.2). A two-stroke entry may rebuild its crank under O.2.2 with ferrous parts only, stroke and rod length unchanged, counterweights resembling the original and assembly weight within 5 per cent. N.2.2, O.2.2
Legal, with conditions1 part
Model-dependent. Four Stroke Ski Lites keeps the crankshaft stock and names no rod allowance, so a four-stroke entry may not change rods. O.2.2 lets a two-stroke entry rebuild its crank with replacement connecting rods, ferrous only, with rod length unchanged and assembly weight within 5 per cent. N.2.2, O.2.2, J.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
Cylinders may be swapped between craft of the same manufacturer, and an aftermarket sleeve may hold the engine within 850 cc only if its ports match the original OEM sleeve, as P.2 adds nothing to O.2.7 for cylinders. O.2.7
Legal, with conditions1 part
Model-dependent. A four-stroke entry stays within the N.2.6 head gasket thickness band, whose figures contradict each other in the rulebook, while P.2.2 lets a two-stroke entry run a modified or aftermarket head gasket. N.2.6, P.2.2
Legal, with conditions1 part
P.2.2 opens only the head gasket, so a two-stroke base gasket stays within O.2.6, at no more than 0.8 mm thick, with 0.5 mm allowed on an engine under 780 cc. O.2.6, P.2.2
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
Model-dependent. Four Stroke Ski Lites gives a four-stroke entry no pump allowance, so its housing and stator stay closed, while P.2.6 lets a two-stroke entry fit an aftermarket or modified impeller housing, stator vane assembly, mounting plate, pump shoe and nozzle, with the pump and nozzle assembly no more than 50 mm longer than OEM. P.1, P.2.6, J.1
Legal, with conditions1 part
Model-dependent. The four-stroke nozzle is not listed in Four Stroke Ski Lites and so stays as supplied. A two-stroke entry may fit an aftermarket or modified nozzle under P.2.6, within the 50 mm overall length limit, which goes beyond the SuperJet angle change and Kawasaki 800 boring of O.5.1. P.1, O.5.1, P.2.6
Legal, with conditions1 part
Model-dependent. Nothing in Four Stroke Ski Lites opens the driveline, so a four-stroke entry keeps it as supplied. On a two-stroke entry P.2.6 allows modified couplers and other pump-area changes provided the original engine-to-pump drive ratio is kept, and an aftermarket shaft is not named. P.1, P.2.6, J.1
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
On both engine types engine-compartment ventilation tubes may be altered, replaced with aftermarket tubes, repositioned on the original ducting or removed, but inlet and outlet openings keep their stock size, and vents may be covered or sealed with no further hood change. N.5.1, O.6.1
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
Model-dependent. Only water strainers and filters may be aftermarket on a four-stroke entry, with the rest of the cooling system and any intercooler fittings as originally equipped (P.1, N.2.4). A two-stroke entry may add aftermarket cooling lines and bypass fittings directed downward or rearward under O.2.4, plus the additional cooling fittings P.2.6 names, with no change to the cylinder or crankcase. N.2.4, O.2.4, P.2.6
Legal2 parts
P.1 applies N.2.7 of Four Stroke Ski Lites to four-stroke entries, which allows aftermarket valves, valve springs and valve spring retainers. P.1, N.2.7
Legal1 part
Inherited from Ski Lites at O.2.5, and made largely moot by the aftermarket expansion chamber P.2.1 permits.
Legal1 part
Two-stroke entries: Full assemblies, broader than Ski Lites O.3.3. P.2.3
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
Named in the general maintenance allowance along with wiring, hoses and clamps. J.7
Legal1 part
May be replaced. J.8
Legal1 part
Two-stroke entries: Aftermarket permitted. P.2.2
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, P, read from the rulebook on 2026-09-11. Read the rule yourself, Ski Limited. 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.
“Ski Limited, IHRA class rules”, BaddJet archive, https://baddjetarchive.com/legality/ihra/ski-limited/
Add the date you read it.
78 parts read · 12 permitted, 36 with conditions · 2026 rulebook