BaddJet Archive Home

Class Legality

IHRA · runabout

Runabout Endurance

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

  • 2Not legal
  • 13OEM part required
  • 21Not permitted, not listed in the rules
  • 26Legal, with conditions
  • 7Legal

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
Seated personal watercraft designed for two or more riders and fitted with a fixed seat, remaining OEM stock in configuration and performance. No model-year list is published.
Displacement limit
325 manufacturer-rated horsepower (W.1.1). There is no capacity figure. The gate is a manufacturer-rated output of 325 horsepower or less with the engine configuration OEM as supplied. W.2.1 permits the engine to be bored, so the control on this class is the power rating rather than a capacity figure.
Licence or tier
Not stated.
Minimum weight
Not stated. W.7.3 separately forbids adding material to increase weight or alter weight distribution.

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 (3)

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 ribbon delete rule at W.3.5 was rewritten on 06.03.2026 and is the newest text in the rulebook. It permits a ribbon delete where the ribbon is the OEM flame-arresting device and airflow is not increased, allows any OEM Yamaha manifold on the SVHO with plastic backdating to metal, and forbids it outright on the Sea-Doo 300 and 325. A general answer about ribbon deletes is wrong for one manufacturer or the other.
  • W.5.2 forbids impeller modification including re-pitching and then carves out the Kawasaki 300 and 310. A catalogue answer here is per model, not per class.
  • The empty W.6 heading means the class has no positive statement about forced induction in a field where most eligible craft are supercharged.

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 sound limit.
  • No hull length or hull width.
  • No displacement ceiling.
  • W.6, titled Turbocharger and Supercharger for Runabout Endurance, is a heading with no text beneath it. Forced induction reaches this class only indirectly through W.3.2, which forbids modification of the turbo or supercharger system, and W.3.6, which addresses the supercharger clutch, pulleys and shafts.

What the rules say (69 parts)

7 permitted outright, 26 permitted with stated conditions, 2 refused by a rule we can quote, 13 held to the original part by a rule we can quote and 21 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

W.7.3.2 permits no external hull modification, so no extension may be added, and the pump cover plate extension under W.5.1 is answered on the ride plate row. W.1, W.7.3.2

OEM part required1 part

W.1 keeps the craft OEM stock and W.2.6 lists no aftermarket manifold or head pipe. The manifold may be drilled and tapped for air fuel ratio and exhaust gas temperature sensor mounts, the OEM resonator between the water box and the outlet may be removed, the water box stays in its OEM configuration, and the external outlet may be relocated or aftermarket. W.1, W.2.6

OEM part required1 part

W.3.5 names no aftermarket manifold. A Yamaha SVHO may run any OEM Yamaha manifold, a plastic one may be backdated to its metal predecessor and the ribbon may be deleted, while a Sea-Doo 300 or 325 keeps its stock manifold and ribbon. The aftermarket component W.3.5 allows is one fitted where needed to hold the original OEM airflow after a ribbon is removed, not a replacement manifold. J.1, W.3.5

OEM part required1 part

The original ECU must stay and may only be reprogrammed, though sensors for air fuel ratio, exhaust gas temperature and detonation are permitted for data logging, and an aftermarket or standalone box is not legal here. W.4.1

OEM part required1 part

W.4 keeps the harness itself OEM, and aftermarket connectors may be fitted to it for reliability only, adding no signal, input or output. W.4, W.4.2

OEM part required1 part

Must remain OEM stock, and no aftermarket unit is listed. The supercharger clutch may be aftermarket if readily available to all competitors from a reputable manufacturer; on the Kawasaki Ultra 300/310 pulleys and tensioners may be modified or aftermarket, and on Yamaha SVHO models the supercharger shafts may be welded. W.1, W.3.6

OEM part required1 part

Must remain OEM. May NOT be modified in any way including re-pitching. EXCEPTION: Kawasaki 300/310 may modify or use aftermarket provided the original diameter is maintained. W.5.2

OEM part required1 part

Must remain OEM stock, and no aftermarket hull is listed. Interior reinforcement of the OEM hull is answered under hull modification. W.1, W.7.3

OEM part required1 part

Seat base and internal structure must stay OEM stock, with no airflow through the seat or base, and the seat must stay attached throughout the race. Height may rise by no more than 50 mm. The 2021 RXP-X keeps its two-piece seat on the original mounts, within 12.7 mm either way, and the 2017 RXT-X races with its removable rear seat installed. W.7.5, W.7.5.1, W.7.5.3, W.7.5.4

OEM part required1 part

Interior structural reinforcement is the only hull work allowed: no external change, nothing that alters the shape, running surface, strakes, chines or ride plate interface, and no added material that acts as ballast or shifts the weight distribution. W.1, W.7.3

Not permitted, not listed in the rules21 parts

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

Legal, with conditions1 part

The OEM resonator between the water box and the outlet may be removed, the water box must remain OEM, air fuel ratio sensor mounts are permitted including drilling and tapping the manifold, and the external outlet may be relocated or aftermarket. W.2.6

Legal, with conditions1 part

The class requires a flame arrester meeting USCG, UL-1111 or SAE J-1928 rather than the OEM one, so a compliant aftermarket arrester reads as allowed. W.3.2

Legal, with conditions1 part

Yamaha SVHO: Aftermarket throttle body adapters permitted. W.3.4

Legal, with conditions1 part

On the Kawasaki Ultra 300 and Ultra 310 an aftermarket fuel regulator and pump are permitted, on those models only. W.3.1

Legal, with conditions1 part

Reprogramming the original unit is the permitted route, and sensors for air fuel ratio, exhaust gas temperature and detonation may be added for data logging only. W.4.1

Legal, with conditions1 part

The one class with a data-logging rule of its own. Air fuel ratio, exhaust gas temperature and detonation sensors are permitted for data logging only, and W.1.3 bans transmitting anything off a moving craft except official transponders, broadcast video and pit radio. Mirrors and speakers may be modified or removed provided seals stay intact. W.4.1, W.1.3, W.7.1

Legal, with conditions1 part

Must retain compression ratio, dome profile, skirt length, skirt shape, material type. Limits: max port chamfer 1 mm, max chamfer angle 30 degrees. W.2.1

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

Bead blast chambers only with valves seated. Ports must NOT be bead blasted or abrasively cleaned. W.2.2

Legal, with conditions1 part

Aftermarket valve retainers are allowed, but W.2.8 names only retainers and guides, so valve springs stay stock on this closed list. W.2.8, J.1

Legal, with conditions1 part

Clutch may be aftermarket if readily available to all competitors from a reputable manufacturer. Kawasaki Ultra 300/310: pulleys and tensioners modifiable. Yamaha SVHO: supercharger shafts may be welded. W.3.6

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

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

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. J.16

Legal, with conditions1 part

Aftermarket covers are allowed if they keep the original seat shape, stay within the height limit (50 mm, or 12.7 mm either way on the 2021 RXP-X) and create no hazard. W.7.5.2, W.7.5.3, W.7.5.4

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

Model-dependent. On the Kawasaki Ultra 300 and Ultra 310 the oil cooler kit, fittings and hoses may be aftermarket (W.2.5). On Sea-Doo craft closed-loop cooling systems must remain in place (W.2.5). On Sea-Doo and Yamaha craft one additional through-hull cooling supply line and pump fitting is allowed, Yamaha may use the engine block anode fitting as a cooling source, and existing fittings stay at OEM thread diameter. W.3.7

Legal1 part

Spark plugs may be aftermarket under the general maintenance allowance, while in this class W.4 keeps the wiring and every other electronic component in its OEM configuration. J.7, W.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

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, W, 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

“Runabout Endurance, IHRA class rules”, BaddJet archive, https://baddjetarchive.com/legality/ihra/runabout-endurance/

Add the date you read it.

69 parts read · 7 permitted, 26 with conditions · 2026 rulebook

Start
BaddJet Class Legality