Replacing Old Fuel Hose on a 2007 Grizzly 660 4x4
Shop parts for a 2007 Yamaha Grizzly 660 4X4 ATV.
The 2007 model year was the last stretch for the Grizzly 660 4x4, and machines from that run are still hauling firewood and covering trail miles today. What has not survived the years nearly as well is the fuel hose. Rubber has a finite life around gasoline and engine heat, and swapping the supply hose is inexpensive preventive work that pays off the first time you do not have to smell fuel in the garage.
What Fails and Why
Two processes destroy fuel hose, and they run at the same time from opposite sides. Externally, engine heat cycles drive out the plasticizers that keep the rubber flexible. The wall stiffens, shrinks slightly, and loses its ability to conform tightly to the barb it is clamped over. Riders in dry country see this sooner because arid air pulls residual moisture from the material and hardens it from the surface inward.
Internally, ethanol-blended pump gas attracts water and slowly degrades the hose liner. That leaves a line that is brittle on the outside and soft on the inside, sometimes shedding fine material into the carburetor where it plugs a jet. Fuel that sits through months of inactivity evaporates and leaves varnish, which cements the hose to its fittings and conceals a slow seep under a hard, dry crust. Neither process is obvious from a glance, so age is a fair reason to replace on principle.
Confirming a Carbureted, Gravity Fed Layout
Settle this before you buy hose. The Grizzly 660 is carbureted throughout its production, including 2007, and it feeds by gravity through a petcock on the tank. That means no electric pump, no pressurized supply, and nothing trapped in the hose after shutdown. Turning the fuel valve to OFF is your complete isolation step. The carburetor has a float bowl drain screw for emptying the bowl into a container. Standard low-pressure fuel hose in the original inside diameter is correct, along with clamps matching the style already on the machine.
Clues on the Ground and Under Throttle
- A wet patch or puddle beneath the quad after it has sat with the valve open
- Gasoline odor lingering around the machine, sharpest near the tank and carburetor
- Visible cracks, splits, or a hardened chalky section anywhere on the hose
- A dust-caked ring at either fitting, formed by fuel that seeped and dried in place
- Bogging under load, sputtering as revs rise, or the feel of an empty tank with fuel still aboard
Note the trap in that list: a gravity system can fail by drawing air through a crack rather than dripping fuel out of it. The 660 will idle happily and then fall flat under demand, with nothing on the floor to point at. Pinch the hose along its whole length and judge it by feel, not just by whether the garage is dry.
Getting Organized Before You Start
Lay out nitrile gloves, eye protection, a drain pan, an approved sealed fuel container, replacement hose in the correct inside diameter, new clamps or a clamp assortment, a flat-blade screwdriver plus pliers for the clamps on the machine, hand tools for the seat and side plastics, and a stack of clean rags.
The important safety point is about vapor behavior. Gasoline fumes are heavier than air, so they sink and collect at floor level under the quad, exactly where your face ends up. An open window six feet off the ground does nothing about that. Do the work outdoors, or open the garage completely and put a fan low to sweep air outward. No smoking, no grinding, no hot incandescent lamps, and keep a fire extinguisher on the floor within reach the whole time.
Taking It Apart
Rotate the petcock to OFF and verify flow has stopped, since an aged valve sometimes weeps past its seal. Slide the pan under the carburetor, back out the float bowl drain screw, and let the bowl empty into your container so the carb side does not spill when the hose comes free. Remove the seat and any plastics that block your view of the run.
Walk both clamps well back along the hose before disturbing the fittings, then cover each joint with a rag. Twist the hose gently to break the varnish bond at the barb rather than hauling on it. If it will not release, slit it lengthwise with a razor and peel it off — that keeps you from bending the brass spigot on the fuel valve or stressing the carburetor inlet, either of which turns an easy afternoon into a much larger repair. Save the old piece as a length gauge.
Trace the routing while it is still in place. On this 4x4 the front differential and driveline hardware fill space a two-wheel-drive machine leaves open, and the hose threads specific frame clearance points on its way down. Reproduce it exactly so the new hose stays clear of exhaust heat and moving components.
Installation and the Final Check
Cut the new hose to match the original length. Excess sags toward the header or rubs a frame edge until it wears through; a short piece keeps tension on the fittings and works itself loose over time. Push each end fully onto its barb until it seats against the shoulder, and install everything dry. Grease, oil, and silicone on the sealing surface give fuel a channel to escape under the clamp, no matter how much torque you apply. Hot water for half a minute makes a stubborn hose end cooperative.
Set the new clamps just behind the raised bead at each fitting and tighten evenly, firm without cutting into the rubber, then return the hose to every original clip and guide. Close the float bowl drain screw and open the fuel valve. Gravity puts fuel at the carburetor within seconds, so watch both joints immediately and check them with a clean, dry finger; moisture on new hose means reseat or retighten now.
Finally, start the 660 and let it idle for several minutes while you inspect both connections with a fresh rag and use your nose alongside your eyes. Reinstall the plastics only after a leak-free run. With the machine still open, look over the tank vent hose and any inline filter, since a blocked vent or clogged filter mimics a failing supply hose closely and is simple to sort out while you are already there.
Related Shopping Categories
Shop Fuel Lines for a 2007 Yamaha Grizzly 660 4X4 ATV.
Shop Fuel Line Clamps for a 2007 Yamaha Grizzly 660 4X4 ATV.
Shop Petcocks for a 2007 Yamaha Grizzly 660 4X4 ATV.
Shop Fuel Filters for a 2007 Yamaha Grizzly 660 4X4 ATV.
Shop Fuel Stabilizer for a 2007 Yamaha Grizzly 660 4X4 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.