Not legal 1 class
Two-stroke exhaust stock. · RAS.4.5
IJSBA · Exhaust
Aftermarket waterbox, IJSBA
Frequently where a stock class draws the line even when the chamber is legal.
This page is IJSBA only, and the bodies do not agree. The same part under IHRA and UIM. Which one applies to you is decided by whoever sanctions the race you enter.
Where it stands, class by class
20 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.
What each answer below means
- Not legal
- This comes off. The rules refuse it in this class.
- OEM part required
- This comes off. Only the part the manufacturer fitted is allowed here.
- Not permitted, not listed in the 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 legal 1 class
Exhaust must remain stock as supplied by the manufacturer. Only a stinger insert and cooling lines are allowed. · SKL.3.6
OEM part required 1 class
Any modification to the water box is prohibited. · FSKL.3.6
OEM part required 1 class
Modifying the original waterbox is prohibited.
OEM part required 1 class
Modifying the OEM waterbox is prohibited. · RAL.4.7
Not permitted, not listed in the rules 3 classes
Not listed in this class document. Illegal under the closed-list principle.
- Fixed Steering Ski Stock · FSSK
- Runabout Rec Lites · RRL
- Ski Stock · SSK
Not permitted, not listed in the rules 1 class
VSKL.3.7 lists manifold, head pipe and expansion chamber only. Waterbox is not listed.
- Vintage Ski Limited · VSKL
Not permitted, not listed in the rules 1 class
No waterbox allowance in SKM.
- Ski Modified · SKM
Legal, with conditions 1 class
Kawasaki, Yamaha and Polaris may relocate and replace with aftermarket. Sea-Doo HX must use an OEM factory HX waterbox with water fittings plugged.
- Sport Spec · section headings, no numbered rules
Legal, with conditions 1 class
The exhaust system, water box included, may be aftermarket provided no hazard is created, and RSS.1 admits only four-stroke engines, so the two-stroke rule keeping the original water box does not arise. · RSS.1, RSS.3.13
Legal 6 classes
Manifold, head pipe, expansion chamber, waterbox and muffler modified or aftermarket.
- Vintage SC · VSC.3.7
- Vintage X2 · VX2.3.7
- Vintage Ski · VSK.3.7
- Freestyle · FREST.3.7
- Ski Grand Prix · SKGP.3.7
- Sport GP · SPGP.5.9
Legal 2 classes
Manifold, connecting pipes, hoses and mufflers modified or aftermarket, with no tuned portion outside the hull.
- Ski Superstock · SKSS.3.8
- Runabout Open / GP · ROP.4.8
Aftermarket waterbox: 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 IJSBA class · where the rulebooks differ · checks on parts the shop sells · how this site reads a rulebook.
Exhaust · two and four stroke · legal in 10 of 20 answered, 2 with conditions