Ski Juniors GP3.2

UIM 2026, 302.01. The rulebook does not state a governing principle for this class.

5Not legal
7OEM part required
17Not permitted, not listed in the rules
19Legal, with conditions
9Legal

Read out of the published UIM rulebook on 2026-09-08, so confirm anything that decides a purchase. The full note is at the foot of the page.

Running the class

Rider requirements: Ages 10-12, reckoned at 31 December; Minor Release Form signed by parent or guardian.
Race duration: 12 minutes + 1 lap.
Riders on the grid: 15.
Entry fee: Free; no proportional travel money paid.
Championship status: World Championship class.

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 rulebook nowhere states in words that GP3.2 uses the 501.02 technical rules. It is an inference from the 800 cc match plus 315.01 saying the general UIM Aquabike rules apply. There is no rule number that makes the link explicit.
The 10-12 band sits below the 315.01 general junior floor of 7; the two are consistent but unreconciled.

What the rules say (57 parts)

9 permitted outright, 19 permitted with stated conditions, 5 refused by a rule we can quote, 7 held to the original part by a rule we can quote and 17 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

The exhaust system must remain entirely of origin as delivered by the manufacturer, so the through-hull outlet flap may not be removed. 501.02.03.03

Through-hull exhaust outlet flap removal · Exhaust

Not legal1 part

Only replaceable-type jets, needle valves and needle valve springs, choke removal and an aftermarket primer. NO OTHER CARBURETTOR MODIFICATIONS. 501.02.04.01

Aftermarket or modified carburettor · Fuel

Not legal1 part

No fuel-injection allowance exists for Ski GP3.

Aftermarket fuel injection system · Fuel

Not legal1 part

No internal modifications of any kind - grinding, surfacing, polishing, machining, shot peening. 501.02.03.02

Full porting service (ports reshaped, runners modified) · Engine

Not legal1 part

Homologated production craft only - 50 specimens, marketed, conformity certificate. 500.02.01

Aftermarket or prototype hull · Hull and handling

OEM part required1 part

The exhaust system must remain entirely of origin as delivered by the manufacturer, so the original expansion chamber is required under 501.02.03.03. 501.02.03.03

Aftermarket expansion chamber / tuned pipe (2-stroke) · Exhaust

OEM part required1 part

The exhaust system must remain entirely of origin as delivered by the manufacturer, so the original water box is required under 501.02.03.03. 501.02.03.03

Aftermarket waterbox · Exhaust

OEM part required1 part

Ski GP3 is a two-stroke class, and 501.02.03.03 keeps its whole exhaust system as the manufacturer delivered it, so the original manifold and head pipe are required. 501.02.01, 501.02.03.03

Aftermarket exhaust manifold / head pipe · Exhaust

OEM part required1 part

OEM fuel tank, pickup, filler, filter, tap assembly and relief valve must be used and may not be modified. 501.02.04.02

Replacement or aftermarket fuel tank · Fuel

OEM part required1 part

Ski GP3 keeps the original equipment charging system, allows no ignition change it does not list, and unlike GP2 prints no flywheel, alternator or flywheel cover allowance. 501.02.05.04, 501.02.05.05

Aftermarket flywheel or alternator (2-stroke) · Ignition

OEM part required1 part

THE OEM CHARGING SYSTEM MUST BE USED. Stated for every production class in both divisions.

Aftermarket charging system / stator · Ignition

OEM part required1 part

The hull may be repaired but not otherwise modified, and a repair may not alter the original configuration by more than 5 mm. 501.02.02-02

Modification of the OEM hull · Hull and handling

Not permitted, not listed in the rules10 parts

Not listed in this class. Illegal under the class's own stock clause.

Aftermarket or modified rotary valve · Fuel
Long-distance fuel filling system (stopper and tank connection) · Fuel
Aftermarket vapour / air separator · Fuel
Aftermarket pump nozzle and directional nozzle · Driveline
Aftermarket driveshaft, couplers, bearing housing · Driveline
Titanium driveshaft, impeller housing or stator vane assembly · Driveline
Aftermarket nozzle trim system (pump-mounted) · Driveline
Aftermarket hull trim tabs · Hull and handling
Ballast weight kits · Hull and handling
Hull extension · Hull and handling