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Class Legality

IHRA · drag

Drag, Sea-Doo Spec

IHRA 2026, DD.4. A closed-list class. The craft must stay stock except where the rules allow otherwise, so anything unlisted is not permitted.

  • 4Not legal
  • 6OEM part required
  • 18Not permitted, not listed in the rules
  • 22Legal, with conditions
  • 19Legal

Read out of the published IHRA rulebook on 2026-09-11, so confirm anything that decides a purchase. The full note is at the foot of the page.

Running the class

Eligible craft
OEM Sea-Doo personal watercraft. A smaller OEM tank from another Sea-Doo may be fitted, and the rulebook gives its own example of a Spark tank in an RXP-X. No model-year list is published.
Displacement limit
No displacement ceiling.
Licence or tier
Not stated.
Minimum weight
Not stated.

Read from the same class section as the part answers. The rider side of the sport, tiers, ages, licences and what gets inspected, is set out across the bodies at Racing.

Open questions on this class (2)

Places where the rulebook contradicts itself, or where a figure could not be settled. Nothing in this list is decided, and it sits here rather than in a footnote because it is what you would want before spending money.

  • The same DD closed-list problem applies.
  • Porting is permitted here and prohibited in Sea-Doo Pro Stock at DD.2. Lightening is permitted here and prohibited there. The Spec class is the more permissive of the two, which is the reverse of how the same two words rank in the closed-course sections.

Sections this rulebook does not contain for this class

Confirmed absent by a targeted read rather than merely unnoticed. In a closed-list class an absent article is why a part reads as not permitted; in an open class it is why one reads as open.

  • No class criteria of any kind.
  • No cooling article.
  • No ignition timing article.

What the rules say (69 parts)

19 permitted outright, 22 permitted with stated conditions, 4 refused by a rule we can quote, 6 held to the original part by a rule we can quote and 18 refused by our reading of the class rather than by a quoted rule. Grouped where the same rule gives the same answer, so two "Not legal" groups can sit side by side under different 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.

Read the refusals as a list of work. Anything below marked Not legal, OEM part required, or Not permitted has to come off the machine, or go back to the standard part, before it races in this class.

Not legal1 part

Bolts, nuts and washers may not be substituted with titanium unless originally equipped. Locking mechanisms are allowed. J.7

Not legal1 part

Nitrous oxide is not permitted, and neither is a turbocharger unless the craft came with one. DD.4

Not legal1 part

DD.4 requires the OEM hull, with lightening the only change it lists, so no extension may be added. DD.4

OEM part required1 part

Must remain OEM. Cable-driven bodies may be bored to newer-model Sea-Doo specifications. DD.4

OEM part required1 part

Sea-Doo Spec keeps the OEM hull and top deck, so no replacement hull may be fitted. DD.4

OEM part required1 part

Must remain OEM. Modifications permitted. DD.4

Not permitted, not listed in the rules18 parts

On a closed list an unlisted modification is not permitted. A.2.2, J.1

Legal, with conditions1 part

Waterbox must be retained; aftermarket permitted with a through-hull exhaust pipe. STRAIGHT PIPES NOT PERMITTED. DD.4

Legal, with conditions1 part

J.7, in the general rules for every class, names wiring as replaceable with aftermarket options, which overrides the closed-list default and covers replacement wiring. Connectors are not named on their own, and J.7 does not open added inputs or outputs, a different harness design or an ECU. J.7

Legal, with conditions1 part

Repairs are allowed for a crack or puncture, but only one damaged area affecting one cylinder bank. No other modification. J.11

Legal, with conditions1 part

May be modified or replaced with an aftermarket part. The original diameter must be maintained in Stock class, and the rulebook never defines which classes that is. J.18.2

Legal, with conditions1 part

May be replaced within OEM specifications. J.18.3

Legal, with conditions1 part

Aftermarket or modified, full-length type with at least one bar parallel to the driveshaft, dropping no more than 12.00mm (0.47 in) below the flat plane of the pump intake. J.18.1

Legal, with conditions1 part

Aftermarket or modified. An extension may not exceed the width of the original plate, and on a ski may not extend more than 100 mm (3.94 in). J.18.1

Legal, with conditions1 part

Replacement trim plates may be used provided they mimic the handling characteristics of the stock plates. J.18.2

Legal, with conditions1 part

Braking devices may be disabled for safety, and reverse buckets and trim motors may be removed or modified to disable them, provided no hazard is created. J.18.4

Legal, with conditions1 part

The top deck must stay OEM, so no aftermarket deck may be fitted, but DD.4 lets it be lightened and drilled for more air. DD.4

Legal, with conditions1 part

Aftermarket, modified, repositioned or removed. Up to two, each no longer than 36 in (91.45 cm), protruding no more than 3.94 in (100 mm) horizontally, at least 6 mm thick with radiused leading edges, and not attached to a planing surface. DD.4, J.16

Legal, with conditions1 part

The seat must be OEM, but modifications are permitted, read here as taking in a replacement cover. DD.4

Legal, with conditions1 part

Replacement bumpers and side rails may be used provided they create no hazard. A permanently affixed nose bumper remains required. J.13, I.17

Legal, with conditions1 part

May be added to adjust handling. Constant mass only, and no other part may be modified to carry it. J.19

Legal, with conditions1 part

Under the general maintenance allowance a cooling hose or clamp may be aftermarket; J.7 names no cooling fitting. J.7

Legal, with conditions1 part

The hull stays OEM, and lightening it is the one change listed, along with drilling plastics and the top deck for more air. DD.4

Legal1 part

Aftermarket intake manifolds are permitted, with no limit stated on design or material. DD.4

Legal1 part

An aftermarket ECU is permitted with no limit stated, which this site reads as covering a reflash, as DD.1 and DD.2 say in terms. DD.4

Legal1 part

Aftermarket pistons are permitted, and unlike the Pro Stock classes factory compression need not be kept. DD.4

Legal1 part

Aftermarket camshafts and cam gears are permitted, with no lift, duration or timing limit stated. DD.4

Legal1 part

Aftermarket valves are permitted, without the OEM specification and no-oversize rule of the Pro Stock and Yamaha Spec classes. DD.4

Legal1 part

May be replaced, as may starters and oil injection systems, with the oil injection system removable or disconnectable. J.8

Legal1 part

Aftermarket intercoolers are permitted, with no size, type or mounting limit stated. DD.4

Legal1 part

Aftermarket nozzles are permitted together with aftermarket pump assemblies, with no length limit stated in the class. DD.4

Legal1 part

Grips, throttle and cables may be modified or aftermarket. The bar must be padded at the mounting bracket or the crossbar padded. J.17.1

Legal1 part

Steering shaft, holder, handlebar holder and cables may be aftermarket, and quick-turn modifications are allowed. J.17.2

Legal1 part

The bilge pump may be modified or disconnected and aftermarket bilge draining systems are permitted, provided they create no hazard. J.10

IHRA 2026, DD.4, read from the rulebook on 2026-09-11. Read the rule yourself. Every IHRA class · where the rulebooks differ · how this site reads a rulebook.

This is one class. Every part below also has a page of its own showing where it stands across every class this body runs, and legality by part is the index of them.

Cite this page

“Drag, Sea-Doo Spec, IHRA class rules”, BaddJet archive, https://baddjetarchive.com/legality/ihra/drag-seadoo-spec/

Add the date you read it.

69 parts read · 19 permitted, 22 with conditions · 2026 rulebook

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