UIM · Engine
Rebuild yes, replacement geometry no.
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.
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.
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.
Legal, within limits 3 classes
Rebuild allowed. Stroke and rod length may NOT change. Bearings must keep original type and dimensions. Counterweights must resemble the original with no new holes or pockets. Total assembly weight within +/-5.00% of OEM. Non-ferrous counterweights, crank pins and connecting rods are prohibited. · 501.02.03
Legal, within limits 1 class
502.02.03
Legal, within limits 1 class
502.03.03
Legal, within limits 1 class
Same constraints. · 501.03.03
No rule, this is an open class 5 classes
No article covering this part. Free under the open-list reading of · GP1.
Crankshaft rebuild components (counterweights, pins, rods, bearings): 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.
Engine · two stroke · legal outright in 6 of 19