Swapping the Fuel Line on Your 2024 GAS GAS EX 300

Shop parts for a 2024 GAS GAS EX 300 Dirt Bike.

A cracked fuel line seems trivial until it strands you at the far end of a trail or drips onto a hot pipe. On a 2024 GAS GAS EX 300, the fuel line is a short, inexpensive piece of rubber doing a job with zero tolerance for failure — and replacing it is well within reach with basic hand tools and about half an hour.

Understand the EX 300 Fuel Delivery First

Fuel delivery on the 2024 GAS GAS EX 300 is handled by injection, so assumptions that apply to older carbureted bikes do not apply here. There is no petcock to close, the line holds pressure after shutdown, and the filter is typically part of the in-tank pump assembly rather than sitting inline where you can see it.

Warning Signs Your EX 300 Needs a New Line

A fuel line rarely fails without hinting first. Run through this list before loading the EX 300 up, particularly if the bike has been sitting.

  • Fuel staining at either fitting. Seepage shows up at the barbs before anywhere else.
  • Persistent gasoline smell. If you smell fuel with the bike cold and untouched, something is leaking.
  • Cracks that appear when you flex the hose. Dry rot hides at rest and reveals itself the moment rubber bends.
  • Swelling or a soft, mushy section. The opposite of hardening and just as bad — usually chemical attack.
  • Surging or dying under load. Restricted flow mimics fuel starvation and gets misdiagnosed as a jetting problem.

Getting Set Up Before You Start

The parts list is short and the tool list shorter. Lay it out before breaking the first connection.

  • Replacement fuel line rated for injection pressure and sized for your 2024 GAS GAS EX 300. Low-pressure carburetor hose is not a substitute.
  • Line-clamping pliers. With no petcock on the EX 300, these are how you stop the tank siphoning while the line is open.
  • New clamps or the correct quick-connect fitting, depending on your connections. Some injected models need no clamp at all.
  • Nitrile gloves and eye protection. Pressurized fuel can spray when a connector releases.
  • A fuel-safe drain container and a funnel.
  • Shop rags positioned at the fitting before you break it loose.

One genuine safety note: gasoline vapor is heavier than air and travels along the floor toward anything that can ignite it. Work outdoors or with the door open, shut off any heater with a pilot light, keep the fuel container capped, and let a hot engine cool first.

Why This Part Wears Out at All

It helps to treat fuel line as a consumable rather than a permanent part. The material is engineered to stay soft and seal against a barbed fitting, and it loses that ability gradually as heat cycling, sun exposure, and plain calendar age push it the same direction — a dry climate does it fastest. Fuel chemistry compounds the problem. Ethanol blends sitting through a long off-season absorb water and begin to separate, which is harder on rubber than fresh fuel and leaves gum behind. On a 2024 GAS GAS EX 300 stored more than ridden, that combination is the usual culprit.

Taking the Failed Hose Off

With no petcock on the 2024 GAS GAS EX 300, the shutoff is mechanical: clamp the fuel line closed with line-clamping pliers upstream of the fitting you plan to open. That isolates the tank and keeps it from siphoning once the connection is broken.

Relieve the pressure before separating anything. Let the bike cool, then wrap a rag around the fitting and release it slowly so residual pressure vents into the rag rather than across the engine. Keep your catch container underneath.

Release the fitting according to type. A quick-connect coupler has a tab, collar, or wire clip that must be depressed or slid back before it will separate; it comes apart with a squeeze and a straight pull, never with a screwdriver. A clamped barb fitting on the EX 300 works like any other — retract the clamp, twist to break the seal, and pull the hose free. If the rubber has hardened onto the fitting, cut it off rather than levering against a throttle body inlet.

Putting the Fresh Hose On

Size the replacement off the original and confirm the hose is rated for a pressurized system. Fuel injection puts real pressure behind the joint, so both the specification and the quality of the cut matter on a 2024 GAS GAS EX 300.

Join the upstream connection first. If the EX 300 uses a self-locking quick-connect, align the halves and push straight in until the mechanism latches, then verify by pulling gently — that click is the difference between a sealed system and a leak under pressure. No clamp is required. Barbed fittings need the hose seated fully over the barb with a clamp placed over that section.

Nothing gets lubricated. Grease or oil on the fitting reduces sealing ability and can gum up a coupler latch, and it has no place in a fuel circuit. With both ends made up, check the run for clearance and kinks, and secure the hose away from the header and any suspension linkage moving through its arc.

Final Checks and the First Start

Let the pliers off the hose and bring the system up to pressure. Switching the ignition on without cranking spins the pump for a few seconds, which is the cleanest way to pressure-test a new connection on a 2024 GAS GAS EX 300. Look hard at both ends before going further.

Next, start the engine and repeat the inspection warm. Vibration plus pressure is the real test, and quick-connect fittings deserve extra scrutiny — verify the lock has clicked home and nothing seeps around the collar. When you find moisture, disassemble and reseat; a coupler cannot be tightened into sealing.

Worth knowing before the tools go away: on an injected EX 300 the fuel filter generally lives inside the tank as part of the pump module, so it is not something you service on the visible line. Dispose of the drained fuel properly, then check the fittings again after a ride or two. For a wider look at what shortens fuel line life, our general guide to replacing a dirt bike fuel line is worth reading.

Related Shopping Categories

Shop Fuel Lines for a 2024 GAS GAS EX 300 Dirt Bike.

Shop Fuel Line Clamps for a 2024 GAS GAS EX 300 Dirt Bike.

Shop Petcocks for a 2024 GAS GAS EX 300 Dirt Bike.

Shop Fuel Filters for a 2024 GAS GAS EX 300 Dirt Bike.

Shop Fuel Stabilizer for a 2024 GAS GAS EX 300 Dirt Bike.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your dirt bike's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.