IJSBA · Fuel

Carb jet kit, needle valve, needle valve spring, IJSBA

The rebuild/tuning tier that stays legal in closed-list classes.

This page is IJSBA only, and the bodies do not agree. The same part under IHRA and UIM. Which one applies to you is decided by whoever sanctions the race you enter.

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This is one body's answer, not the sport's. You are bound by whichever body sanctions the event you enter. If you race more than one series, build to the stricter answer. The differences are set out in the rulebook comparison.

Where it stands, class by class

20 classes, grouped where the same rule gives the same answer rather than listed one by one, because an answer that holds for a class usually holds for every class that borrows its rules.

What each answer below means

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.

Not permitted, not listed in the rules 2 classes

Not listed in this class document. Illegal under the closed-list principle.

• Four Stroke Ski Lites · FSKL
• Ski Modified · SKM

Legal, with conditions 1 class

Carburetors may be modified or aftermarket provided they do not vent or spill fuel at any attitude, with or without the engine running, and jets and needles are inside the carburetor. · ROP.5.4

• Runabout Open / GP

Legal 8 classes

The carburetor may be modified or aftermarket provided it cannot vent or spill fuel at any attitude, which covers its jets, needle valves and needle valve springs.

• Vintage Ski Limited · VSKL.4.1
• Ski Superstock · SKSS.5.4
• Vintage SC · VSC.4.1
• Vintage X2 · VX2.4.1
• Vintage Ski · VSK.4.1
• Freestyle · FREST.4.1, FREST.8.4
• Ski Grand Prix · SKGP.4.1, SKGP.8.4
• Sport GP · SPGP.6.4, SPGP.7.1

Legal 7 classes

Carburetor jets (replaceable type), needle valves and needle valve springs may be changed.

• Fixed Steering Ski Stock · FSSK.4.2
• Runabout Rec Lites · RRL.4.2
• Ski Stock · SSK.4.2
• Runabout Naturally Aspirated · RNA.5.2, RNA.6.1
• Runabout Stock · RAS.6.1
• Runabout Limited · RAL.5.5
• Runabout Superstock · RSS.5.5, RSS.7.1

Legal 1 class

Changes to replaceable-type jets, needle valve and needle valve spring. · SKL.4.1

• Ski Lites

Legal 1 class

Rejetting and de-choking explicitly allowed on all models including the HX.

• Sport Spec · section headings, no numbered rules

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What we corrected here, and when

• Runabout Limited. Corrected 2026-10-07: this row read as not permitted, not listed in the rules, until RAL.5.5 was read against it; the clause lists these parts by name.
• Runabout Open / GP. Corrected 2026-10-01: this row read as unanswered until ROP.5.4 was read against it, and the clause opens the carburetor these parts sit in.

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Carb jet kit, needle valve, needle valve spring: if the rule your class applies reads differently to you, or the rulebook has changed since this was read, ask. We answer with the section we read it from, or that we have not read it. Ask a rules question.

Every IJSBA class · where the rulebooks differ · checks on parts the shop sells · how this site reads a rulebook.