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Four-Stroke Ski Lites

IHRA · ski

Four-Stroke Ski Lites

IHRA2026, N. A closed-list class. The craft must stay stock except where the rules allow otherwise, so anything unlisted is not permitted.

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.

  • N.2.6 carries the same self-contradictory head gasket rule as L.2.6 and O.2.6, with the same wrong unit conversion. 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 or top deck article.
  • No forced induction article.

What the rules say (64 parts)

27 permitted outright, 29 answered by our reading of the class rather than by a quoted rule, 0 the rules do not settle. Grouped by the answer, because an open class gives one answer to most questions and printing it once per part would say the same sentence forty times.

Not permitted, not listed in the rulesOur reading, not a rule we can quote at you. This class requires the craft to stay stock except where the rules allow otherwise, and this part is not on the list.

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, keeping the same input and output count, with no sensor added, so an aftermarket or standalone box is not legal here. N.4.1

OEM part required1 part

Must remain OEM, with only water strainers and filters aftermarket and the intercooler assembly and its fittings OEM. N.2.4

Not permitted, not listed in the rules29 parts

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

Legal, within limits1 part

Intake manifold including screens and spark suppressors must remain stock. N.3.1

Legal, within limits1 part

Reprogramming the original unit is the permitted route, keeping the same input and output count, with no sensor added. N.4.1

Legal, within limits1 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, within limits1 part

Boring is allowed provided the piston keeps its compression ratio, dome profile, skirt length and material type, and chambers are bead blasted only with no steel wool or Scotch-Brite. N.2.1

Legal, within limits1 part

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

Legal, within limits1 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, within limits1 part

May be replaced within OEM specifications. J.18.3

Legal, within limits1 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, within limits1 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, within limits1 part

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

Legal, within limits1 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, within limits1 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, within limits1 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, within limits1 part

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

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, N, read from the rulebook on 2026-09-11, not verified by a racer. Read the rule yourself. Every IHRA class · where the rulebooks differ.

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.

64 parts read · 27 permitted outright · 2026 rulebook

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