How to Put a New Fuel Line on a 2002 Grizzly 660 4x4
Shop parts for a 2002 Yamaha Grizzly 660 4X4 ATV.
When the 2002 Grizzly 660 4x4 arrived it was the biggest, torquiest utility quad Yamaha had built, and the platform's reputation for outlasting its owners is well earned. The fuel hose, however, does not last forever. Rubber is the one part of a fuel system with a clock running on it, and on a machine two decades into service that clock has long since run out.
Confirming What Feeds the Engine
Before you buy anything, settle the fuel system question. The Grizzly 660 is carbureted, with a petcock on the tank feeding fuel downhill through rubber hose to the carburetor. There is no electric pump, no pressurized supply, and nothing to depressurize. Rotating the fuel valve to OFF stops the flow, which simplifies the entire job. The carburetor also has a float bowl drain screw, letting you empty the bowl into a container before anything comes apart. Ordinary low-pressure fuel hose in the original inside diameter is the correct part to buy.
The Slow Death of Rubber Hose
Hose failure is gradual and mostly chemical. Each time the big single heats up and cools down, a small amount of the plasticizer content that keeps the rubber flexible escapes. Two decades of that leaves a wall that is stiff, slightly shrunken, and unable to conform to the barb it is clamped to. Dry climates push it along faster, drawing moisture from the material and producing the fine surface checking that eventually becomes real cracks.
Ethanol-blended pump gas comes at it from inside. Alcohol pulls water into the fuel and degrades the hose liner over time, so the interior can be soft and shedding while the exterior has gone glassy. Loose material heads for the carburetor jets. Fuel that sits during an off season evaporates and leaves varnish that bonds the hose to its fittings and hides slow seepage under a hard crust. None of this is visible from a distance, which is why age alone is a reason to replace.
How a Failing Line Shows Itself
- Fuel pooling or staining the ground beneath the quad after it sits with the valve open
- A gasoline smell that hangs around the machine, sharpest near the tank and carburetor
- Visible cracking, splitting, or a hardened chalky patch along the hose
- A dust-caked wet ring at a fitting, where seeped fuel has dried and trapped grit
- The 660 bogging under load, sputtering as revs climb, or acting empty with fuel still in the tank
Remember that a gravity system can fail without dripping. A crack above the fuel level lets air in rather than letting fuel out, which starves the carburetor under demand while leaving no puddle to find. If your Grizzly runs cleanly at light throttle and falls apart when working, the supply hose is a prime suspect.
Assembling Tools and Making the Area Safe
Lay out gloves, eye protection, a drain pan, an approved sealed container, replacement hose in the correct inside diameter, new clamps or a clamp assortment, a flat-blade screwdriver and pliers for the existing clamps, hand tools for the seat and plastics, and a stack of clean rags. Line-clamping pliers are handy for isolating a section without draining the tank, though the petcock covers your shutoff needs.
The safety point that actually matters here is ventilation. Gasoline vapor is heavier than air and sinks, collecting at floor level under the machine and around your knees where you neither see nor smell it well. Do the work outdoors, or open the garage bay completely and set a fan low to move air out across the floor. Eliminate flames, sparks, and hot incandescent lamps, and keep an extinguisher on the ground within reach.
Extracting the Old Hose
Close the fuel valve and confirm that flow has stopped, because a worn petcock will sometimes seep past its seal. Slide the drain pan under the carburetor, back the float bowl drain screw out, and let the bowl empty into your container so the carb side does not dump on you later. Remove the seat and whatever bodywork blocks a clear view of the hose run.
Walk both clamps well back along the hose before disturbing the fittings, then drape a rag over each joint. Twist the hose gently to break the varnish bond at the barb instead of hauling on it. Hose that stays locked on should be slit lengthwise with a razor blade and peeled away, which protects the brass spigot on the petcock and the carburetor inlet from being bent or cracked. Keep the removed piece as a length reference.
Watch the routing as it comes out. This being a 4x4, the front differential and its driveline hardware fill space that a two-wheel-drive quad leaves open, and the hose threads through particular frame clearance points to stay clear of heat and movement. A photo of each clip is worth the ten seconds.
Fitting the Replacement
Cut the new hose to the length of the old one. Extra hose sags toward the header or works against a frame edge until it wears through, while a piece cut short puts constant tension on both fittings. Push each end fully onto its barb until it bottoms against the shoulder, and assemble everything dry. Grease, oil, and silicone on a fuel fitting are the classic recipe for a weep that clamp torque cannot fix. If a hose end resists, warm it in hot water for half a minute.
Set the new clamps immediately behind the raised bead at each fitting and tighten them evenly — firm enough to seal, not tight enough to bite into the rubber. Return the hose to every original clip and guide, then check clearance to the exhaust and the front driveline by hand before you close anything up.
Restoring Flow and Verifying the Seal
Snug the float bowl drain screw, open the fuel valve, and watch. Gravity fills the bowl within seconds, so a bad joint gives itself away almost immediately. Check both the valve end and the carburetor end with a clean, dry finger; even a trace of dampness on new rubber means something wants another look before you ride.
Start the 660 next and let it idle for several minutes while you inspect both connections again with a fresh rag, using your nose as well as your eyes. Reinstall the bodywork only after a clean, leak-free run. Since you are already in there, glance at the tank vent hose and any inline filter your machine carries, because a pinched vent or plugged filter creates the same starved-for-fuel behavior you set out to fix.
Related Shopping Categories
Shop Fuel Lines for a 2002 Yamaha Grizzly 660 4X4 ATV.
Shop Fuel Line Clamps for a 2002 Yamaha Grizzly 660 4X4 ATV.
Shop Petcocks for a 2002 Yamaha Grizzly 660 4X4 ATV.
Shop Fuel Filters for a 2002 Yamaha Grizzly 660 4X4 ATV.
Shop Fuel Stabilizer for a 2002 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.