The one exhaust part that is legal in the tightest two-stroke stock classes.
This page is IJSBA only, and the bodies do not
agree. The same part under IHRA. Which one applies to you is decided by whoever sanctions the race you enter.
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.
This is the only pipe-adjacent part that is legal in Ski Lites.
12 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.
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 4 classes
Not listed in this class document. Illegal under the closed-list principle.
The exhaust system, which this clause names as the manifold, head pipe, expansion chamber, waterbox and mufflers, may be modified or aftermarket, and an insert in the stinger is part of it. No tuned portion of the exhaust may protrude outside the hull.
Freestyle. Corrected 2026-10-01: this row read as unanswered until FREST.3.7 was read against it, and the clause opens the whole exhaust system.
Ski Grand Prix. Corrected 2026-10-01: this row read as unanswered until SKGP.3.7 was read against it, and the clause opens the whole exhaust system.
Sport GP. Corrected 2026-10-01: this row read as unanswered until SPGP.4.8 was read against it, and the clause opens the whole exhaust system.
Vintage SC. Corrected 2026-10-01: this row read as unanswered until VSC.3.7 was read against it, and the clause opens the whole exhaust system.
Vintage Ski. Corrected 2026-10-01: this row read as unanswered until VSK.3.7 was read against it, and the clause opens the whole exhaust system.
Vintage X2. Corrected 2026-10-01: this row read as unanswered until VX2.3.7 was read against it, and the clause opens the whole exhaust system.
Stinger reducer insert + cooling line: 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.