OEM part required 2 classes
Must remain OEM. Timing may be adjusted.
- Runabout Lites · AA.2.3
- Four-Stroke Ski Lites · N.2.3
IHRA · Engine
Aftermarket camshafts, IHRA
IHRA answers this part for 24 of its classes. 8 of those answers permit the part outright and 1 permit it with stated conditions, leaving 15 that do not. 3 of the ones that do not are classes we read as open rather than as refusing it. 6 are inferred from how the class is written rather than quoted from a rule naming this part.
This page is IHRA only, and the bodies do not agree. The same part under IJSBA and UIM. Which one applies to you is decided by whoever sanctions the race you enter.
Where it stands, class by class
24 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
- 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.
- No rule, this is an open class
- Probably keep it. The class carries no stock clause at all, so anything unlisted appears to be open. The rulebook does not say so in terms, and this is our reading rather than a permission anybody wrote down.
OEM part required 2 classes
Must remain OEM. Timing adjustments allowed.
- Runabout GP2 · Y.2.3
- Runabout GP3 · Z.2.3
OEM part required 2 classes
Must remain OEM. Timing may be altered. Adjustable timing sprockets may be installed.
- Ski 1100 Modified · R.2.3
- Ski 1500 Modified · Q.2.3
OEM part required 1 class
Must remain OEM. Timing adjustable within limits; adjustable timing sprockets permitted. · L.2.3
OEM part required 1 class
Must remain OEM. Interchangeable between WaveRunner models. · DD.1
OEM part required 1 class
Four-stroke entries keep stock camshafts under P.1, with replacement bearings or shells to the original specification and the cam timing open to adjustment. · P.1, N.2.3
Not permitted, not listed in the rules 3 classes
On a closed list an unlisted modification is not permitted. · A.2.2, J.1
Legal, with conditions 1 class
Cam shaft gears may be welded. · W.2.4
Legal 4 classes
Aftermarket camshafts and cam gears are permitted, with no lift, duration or timing limit stated.
- Drag, Sea-Doo Pro Stock · DD.2
- Drag, Yamaha Spec · DD.3
- Drag, Sea-Doo Spec · DD.4
- Drag, Super Stock · DD.5
Legal 1 class
Four-stroke entries: Aftermarket permitted. · BB.2.3
Legal 1 class
Camshaft count unchanged; original bearing type and dimensions. · K.2.3
Legal 1 class
Four-stroke entries: Camshaft count unchanged, original bearing type and dimensions, activation method unchanged. · V.4.7
Legal 1 class
Aftermarket camshafts are allowed and cam timing may be adjusted, with no limit on camshaft count or bearing type stated. · X.2.8
No rule, this is an open class 2 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.
- Drag, Stand Up Unlimited · DD.10
- Drag, Unlimited · DD.6
No rule, this is an open class 1 class
No restriction in section CC, and CC.1 permits any modification it does not restrict.
- Freestyle · CC
Aftermarket camshafts: 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 · checks on parts the shop sells · how this site reads a rulebook.
Engine · four stroke · legal in 9 of 24 answered, 1 with conditions