Not permitted, not listed in the rules 4 classes
On a closed list an unlisted modification is not permitted. · A.2.2, J.1
IHRA · Fuel
IHRA answers this part for 14 of its classes. 6 of those answers are permissions, with or without limits attached, and 8 are not. 8 are inferred from how the class is written rather than quoted from a rule naming this part.
14 classes, grouped by the answer rather than listed one by one, because an answer that holds for a class usually holds for every class that borrows its rules.
Not permitted, not listed in the rules Our 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.
No rule, this is an open class Our reading, not a rule we can quote at you. This class carries no stock clause at all, so anything unlisted appears to be open. The rulebook does not say so in terms.
Not permitted, not listed in the rules 4 classes
On a closed list an unlisted modification is not permitted. · A.2.2, J.1
Legal, within limits 1 class
Reed petals may be modified or aftermarket. The reed cage assembly must remain OE. · O.3.3
Legal 3 classes
Aftermarket permitted.
Legal 1 class
Two-stroke entries: Full assemblies, broader than Ski Lites O.3.3. · P.2.3
Legal 1 class
Two-stroke entries: Aftermarket permitted. · BB.5.6
No rule, this is an open class 3 classes
The class states only what it bans and calls itself run what you brung, against a section DD preamble that says anything unlisted is illegal.
No rule, this is an open class 1 class
No restriction in section CC, and CC.1 permits any modification it does not restrict.
Aftermarket reed valve assembly: 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 IHRA class · where the rulebooks differ · signed checks on parts the shop sells.
Fuel ยท two stroke ยท legal outright in 6 of 14