UIM · Engine

Full porting service (ports reshaped, runners modified)

UIM never permits porting below GP1 in either division.

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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.

IJSBA opens full porting at Superstock. UIM does not open it until GP1. Porting work sold to a UIM racer below GP1 is money spent on an illegal ski.

Where it stands, class by class

24 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. 8 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.

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 legal 3 classes

502.01.03-01

• Runabout GP4 · 502.01
• Runabout Juniors GP4 · 302.01 · borrows another class
• Runabout Ladies GP4 · 302.01.01 · borrows another class

Not legal 3 classes

No internal modifications of any kind - grinding, surfacing, polishing, machining, shot peening. · 501.02.03.02

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

Not legal 2 classes

No internal engine modifications of any kind; ports may not be cleaned with abrasive material. · 501.01.03.01

• Ski Division GP4
• Ski Juniors GP4 · borrows another class

Not legal 1 class

502.02.03-02

• Runabout GP3 · 502.02

Not legal 1 class

502.03.03-05

• Runabout GP2 · 502.03

Not legal 1 class

No internal modifications of any kind on any engine component. · 501.03.03.05

• Ski Division GP2

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

No rule, this is an open class 5 classes

No engine article.

• Ski Division GP1 · 501.04
• Runabout GP1 · 502.04
• Runabout Veterans GP1 · 302.01.05 · borrows another class
• Ski Ladies GP1 · 314 · borrows another class
• Ski Veterans GP1 · 302.01.05 · borrows another class

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Full porting service (ports reshaped, runners modified): 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.