Replacing the Fuel Line on a 2016 Kymco MXU 700i

Shop parts for a 2016 Kymco MXU 700i ATV.

The MXU 700i sits at the top of the utility lineup, and the plumbing reflects it. This is a fuel-injected machine with a pump inside the tank, a pressurized line running forward to the throttle body, and no petcock anywhere in the system. That single distinction shapes the entire repair. Where a carbureted quad lets you close a valve and walk away, here you interrupt the pump electrically, bleed the pressure out, and only then start loosening fittings.

Access and Routing on a 4x4 Chassis

Before any tools come out, get a clear view of what you are working on. Remove the seat and enough plastic that the tank fitting and the run toward the throttle body are both visible at the same time. Reaching blindly through a gap is how clips get broken and fittings get bent. Photograph the routing, every retaining clip, and each point where the hose passes close to structure.

Four-wheel drive matters here in terms of access rather than procedure. Front differential hardware and extra frame crossmembers crowd the area that the fuel line has to cross, so the hose takes a slightly longer and less direct path than it would on a two-wheel-drive quad. Reproducing that path exactly keeps the new line clear of the front driveline and away from anything that moves with suspension travel.

How the Original Hose Wore Out

Fuel hose fails on two fronts simultaneously. The plasticizers that keep the rubber pliable slowly migrate out of the material and evaporate, and the wall left behind is hard and glassy. Heat cycling from the 695cc single sitting nearby accelerates the loss, and once the hose cannot flex, engine vibration and chassis movement start working cracks into the surface. Machines kept in hot, arid country get there sooner, because low humidity pulls moisture out of the hose wall.

The inner liner degrades chemically at the same time. Ethanol-blended gasoline attracts water vapor, and that mixture softens the liner until it swells and begins releasing fine material toward the injector. Fuel left standing during long idle periods adds gum and varnish, which narrow the flow path and bond the hose firmly to its barbs. Since this circuit carries pressure rather than a simple gravity head, a wall thinned by that combination is under load every time the pump cycles.

What a Failing Line Looks and Smells Like

  • A gasoline odor around the tank, sharpest in the first minutes after shutdown while pressure is still trapped
  • A damp spot on the skid plate or garage floor, keeping in mind that pressurized fuel often atomizes and evaporates before it drips
  • Surface cracking, chalky texture, or a stiffened length that holds a crease when squeezed
  • Fuel-stained dust caked in a ring at a fitting, which marks slow weeping under pressure
  • Bogging under load, a stumble on hard acceleration, or a lean-running feel at higher revs

Restriction hides better than leakage. The big single draws very little fuel at idle, so a hose swollen nearly shut internally can idle smoothly in the driveway and only fall flat when you ask it to pull.

Tools, Parts, and Handling Gasoline Safely

  • Nitrile or rubber gloves and eye protection
  • An approved metal or fuel-rated plastic container for the fuel you capture
  • Replacement hose rated for fuel-injection pressure, matched to the original inside diameter, not carburetor-grade hose
  • Clamps appropriate to your fitting style, plus a release tool if you find a self-locking quick-connect
  • Line-clamping pliers, which do the job the missing petcock would have done
  • A socket set, screwdrivers, pliers, a razor knife, and a generous pile of rags

The gasoline warning is worth stating plainly. Vapor from an open fuel line is heavier than air, so it sinks to floor level and spreads along the ground toward any ignition source in the space. Ventilation low in the room is the part that protects you: open the main door fully and set a fan on the floor pushing air out, or better still work outdoors. Shut off water heaters and furnaces with standing pilot flames, keep the battery disconnected while the system is open, keep chargers and hot work lights well away, and let fuel-soaked rags dry outside rather than sealing them in a can.

Depressurizing and Pulling the Old Line

Remove the fuel pump fuse or relay, then crank the engine briefly until it stalls. That burns off most of the pressure standing in the circuit. Turn the key off and disconnect the battery negative cable so the pump cannot energize while a connection is open. Slide a drain pan into position and drape a rag over the first fitting you break, because a bled line still holds residual fuel that will run out.

Where a clamp secures the hose, walk it back along the rubber before disturbing the joint. Where a self-locking quick-connect is fitted, depress the locking tabs squarely and pull straight off without prying sideways, since a plastic collar that has spent years in an engine bay cracks rather than releases when levered. Clamping pliers close off any low-pressure section that would otherwise siphon while you work.

Rotate the hose gently to shear the dried varnish bond at each barb rather than pulling hard on the fitting. If a section will not let go, split it lengthwise with the razor and peel it away. The tank spigot and the throttle body inlet are both far more expensive than a length of hose, and both bend or crack with surprisingly little force.

Fitting the New Line and Proving It Holds

Cut the replacement to the same length as the piece you removed. Extra hose sags into the front driveline or wears through against a frame tube, and a short piece keeps tension on both fittings as the engine rocks on its mounts. Push each end onto its barb dry until it seats fully past the raised bead.

Keep every lubricant off the fittings. Grease, oil, or silicone spray on a sealing face gives pressurized fuel a path to migrate out from under the hose, and adding clamp tension does not close it. If the hose is too stiff to seat, dip the end in hot water for half a minute and it will slide on unaided. Set new clamps just behind the bead at each end and tighten evenly until the hose no longer rotates by hand. On a quick-connect, push until the collar clicks and then tug firmly to confirm the latch engaged, and leave that joint clamp-free as designed. Return the hose to its factory clips, clear of exhaust heat and the front driveline.

Reinstall the pump fuse, Reconnect the battery, and cycle the key on and off several times without starting. Each cycle runs the pump and pressurizes the line, which is exactly the condition in which a marginal joint gives itself away while everything is still dry. Check both connections by sight and by touch, then start the engine and inspect again with a clean rag while it idles and revs. Several minutes of dry running earns the plastics going back on. One closing note: the fuel filter on this machine is part of the in-tank pump module rather than an inline element, so if delivery still feels soft after a clean install, that is the next place to look.

Related Shopping Categories

Shop Fuel Lines for a 2016 Kymco MXU 700i ATV.

Shop Fuel Line Clamps for a 2016 Kymco MXU 700i ATV.

Shop Petcocks for a 2016 Kymco MXU 700i ATV.

Shop Fuel Filters for a 2016 Kymco MXU 700i ATV.

Shop Fuel Stabilizer for a 2016 Kymco MXU 700i ATV.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your ATV'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.