UIM · Engine

Aftermarket cylinder head (2-stroke)

UIM answers this part for 19 of its classes. 2 of those answers are permissions, with or without limits attached, and 17 are not. 9 are inferred from how the class is written rather than quoted from a rule naming this part. 5 are inherited from a parent class the rulebook points at.

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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, and where both govern you, you are held to the stricter of the two. The differences are set out in the rulebook comparison.

Where it stands, class by class

19 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. 5 of them publish no component rules of their own and are marked below; for those, the link to the parent class is read from the categories table rather than stated in the rulebook.

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 3 classes

No aftermarket head allowance in · 501.02.

• Ski Division GP3
• Ski Juniors GP3.2 · borrows another class
• Ski Juniors GP3.3 · borrows another class

Not permitted, not listed in the rules 1 class

Not listed in this class. Illegal under the class's own stock clause.

• Runabout GP3 · 502.02

Governed by the parent class 8 classes

No component rules are published for this class and no single parent class is named, so this part cannot be answered for it. That is an absence in the rulebook, not a permission.

• Endurance · 317.03
• Freestyle Amateur · 312
• Freestyle Free · 312
• Jet Raid · 317.01
• Offshore · 317.02
• Parallel Slalom · 313
• Ski Future Electric (SFE) · 302.01
• UIM Hydro-Fly · 900

Legal 1 class

502.03.03-06

• Runabout GP2 · 502.03

Legal 1 class

Cylinder head and gasket may be modified or aftermarket. · 501.03.03

• Ski Division GP2

No rule, this is an open class 5 classes

No article covering this part. Free under the open-list reading of · GP1.

• Ski Division GP1
• Runabout GP1
• Runabout Veterans GP1 · borrows another class
• Ski Ladies GP1 · borrows another class
• Ski Veterans GP1 · borrows another class

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Aftermarket cylinder head (2-stroke): 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 UIM class · where the rulebooks differ · signed checks on parts the shop sells.