Not legal1 part
Chamfer only. RAL.3.1
IJSBA · runabout
IJSBA2022, RAL. A closed-list class. The craft must stay stock except where the rules allow otherwise, so anything unlisted is not permitted.
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.
43 permitted outright, 3 answered by our reading of the class rather than by a quoted rule, 4 the rules do not settle. Grouped by the answer, because an open class gives one answer to most questions and printing it once per part would say the same sentence forty times.
Not permitted, not listed in the rulesOur reading, not a rule we can quote at you. This class requires the craft to stay stock except where the rules allow otherwise, and this part is not on the list.
Not legal1 part
Chamfer only. RAL.3.1
Not legal1 part
RAL.9.1
Not legal1 part
RAL.2.6
Not legal1 part
No other modifications to the hood, covers and cowlings included. RAL.2.14
Not legal1 part
Explicitly prohibited by this class document.
OEM part required1 part
Modifying the OEM waterbox is prohibited. RAL.4.7
OEM part required1 part
OEM tank, filler and relief valve, unmodified. RAL.6.5
OEM part required1 part
Stock as supplied. No plate angle change, no housing modification, no spacers behind it. RAL.5.3
Not permitted, not listed in the rules3 parts
Not listed in this class document. Illegal under the closed-list principle.
The rules do not say1 part
Four-stroke exhaust is genuinely not addressed in RAL. Resolve via RAL.1.1 inheritance from Stock.
Governed by the parent class1 part
Resolve via RAL.1.1 inheritance.
Governed by the parent class1 part
Not restated in this class. Resolve up the inheritance chain.
Governed by the parent class1 part
Not restated - resolve via RAL.1.1 inheritance from Stock.
Legal, within limits2 parts
Permitted subject to the universal limits in ijsba-globals.yaml constants.
Legal, within limits1 part
Two-stroke chamber allowed; exit may not be relocated, OEM waterbox may not be modified, exit opening may not be oversized. RAL.4.7
Legal, within limits1 part
Through-hull flap may be removed; the exit may not be relocated. RAL.4.7
Legal, within limits1 part
ECU may be modified OR aftermarket, provided it offers no additional inputs or outputs and uses original connections. RAL.7.2
Legal, within limits1 part
Must fit the OEM battery box and be securely fastened. GP/Open/Freestyle/Sport GP additionally allow an additional battery, a new box and relocation.
Legal, within limits1 part
Machining cylinders for girdle-system heads allowed. RAL.4.1
Legal, within limits1 part
Non-OEM-replica pistons require written IJSBA approval. RAL.3.3
Legal, within limits1 part
May be rebuilt or replaced provided counterweight shape, dimensions and material type, OEM stroke, rod length and journal diameters are retained; +/-5.00% assembly weight. RAL.3.3
Legal, within limits1 part
OEM rod length and journal diameters retained.
Legal, within limits1 part
Aftermarket retainers with OEM springs; valves, seats, springs and pushrods may be modified or aftermarket. Titanium prohibited unless originally equipped.
Legal, within limits1 part
Impeller HOUSING must remain stock; all internals may be aftermarket. RAL.5.1
Legal, within limits1 part
Extension may not be wider than the OEM plate, sides must be connected and radiused, and no fins, rudders or skegs. Max extension beyond the OEM plate: 100.00mm (3.94 in) Ski and Sport, 177.80mm (7.00 in) Runabout.
Legal, within limits1 part
Full-length type with at least one bar parallel to the drive shaft, all leading edges radiused, extending no more than 12.00mm (0.47 in) below the flat plane of the pump intake area.
Legal, within limits1 part
Max TWO. Max 63.5mm drop - increased from Stock.
Legal, within limits1 part
The handlebar must be padded at the mounting bracket, or the crossbar padded if fitted. This is a tech-inspection item.
Legal, within limits1 part
Padding and/or mat kits may be added in every class. Where footwells exist they must be BLOCKED OFF during competition with no indentation into the footwell sides.
Legal, within limits1 part
Replacement bumpers allowed provided no hazard is created. A soft flexible water-spray deflector may attach to the hull sides or bond flange, not extending beyond the perimeter of the OE bumper or side moldings as measured by plumb line. A permanently affixed IJSBA-approved nose bumper is REQUIRED under GEN.8.12.
Legal, within limits1 part
Allowed in essentially every class. Universal prohibitions: no manually controlled devices that alter cooling water flow during operation, no electronically controlled valves or water injection unless original equipment, and in most stock classes no NEW fittings added to the cylinder head, cylinder or crankcase.
Legal, within limits1 part
Fixed-type or automatic valves only. Thermostats, pressure regulators and solenoids qualify. Manual actuation of any kind during operation is prohibited everywhere.
Legal, within limits1 part
Constant mass only, within the normally exposed areas of the hull, creating no hazard and requiring no modification or relocation of other parts. Water and any other fluid ballast is prohibited in every class.
Legal5 parts
Explicitly permitted by this class document.
Legal1 part
Two-stroke reed and rotary valves aftermarket.
Legal1 part
Must meet USCG, SAE J-1928 Marine or UL-1111 Marine backfire flame arrester standards.
Legal1 part
Fuel injectors modified or aftermarket.
Legal1 part
Modified or aftermarket filler cap allowed provided no hazard is created. The FILLER and RELIEF VALVE themselves must stay OEM.
Legal1 part
RAL.8
Legal1 part
Aftermarket spark plugs of a different heat range are allowed in every class that addresses them.
Legal1 part
Two-stroke cylinder head and gasket aftermarket.
Legal1 part
Camshafts may be modified or aftermarket.
Legal1 part
ALL internal supercharger or turbocharger parts may be modified or aftermarket. Pulleys and tensioners too. A spacer may be used to fit a larger impeller. RAL.5.1
Legal1 part
Intercoolers may be modified or aftermarket. Mechanical intercooler pressure relief valves permitted. RAL.5.1, RAL.3.6
Legal1 part
RAL.9.1
Legal1 part
Fixed-position only. RAL.2.6
Legal1 part
Aftermarket steering shaft, steering shaft holder, handlebar holder and steering cables are allowed. Quick-turn modifications that alter the steering ratio are allowed in most stock classes.
Legal1 part
Aftermarket seat per the Appendix provisions. The Stock OEM-base requirement is lifted. RAL.2.10
Legal1 part
The original bilge pump may be modified or disconnected and aftermarket bilge draining systems are allowed, provided no hazard is created.
Legal1 part
Replacement engine mounts are allowed in every class that addresses them. Ski GP, Vintage and Freestyle additionally allow a modified or aftermarket ENGINE BED with the engine repositioned in the hull.
Legal1 part
Replacement starter motor and bendix are allowed in every class that addresses them.
IJSBA 2022, RAL, read from the rulebook on 2026-09-07, not verified by a racer. Read the rule yourself, Runabout Limited. Every IJSBA class · where the rulebooks differ.
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.
58 parts read ยท 43 permitted outright ยท 2022 rulebook