Inspecting and Replacing CV Boots on the 1987 Yamaha Bigbear 350 4X4
Shop parts for a 1987 Yamaha Bigbear 350 4X4 ATV.
What Damages CV Boots on the Bigbear 350 4X4
On the 1987 Yamaha Bigbear 350 4X4, CV boots protect the joints on both the front and rear axles—four positions in total. A utility ATV in regular work use exposes all four boot positions to conditions that accelerate wear beyond what recreational mileage alone would cause. Sustained torque loads during hauling or plowing, mud that coats the boot exterior with abrasive material, water submersion that tests the clamp seals, and impact from rocks and debris during field or trail work all contribute to boot wear. The front outer boots face the additional stress of operating at full steering lock simultaneously with suspension compression, which puts the maximum flex demand on the rubber at the fold lines.
All four boot positions age through the same UV degradation process regardless of operating conditions. The rubber compound hardens over time, losing the elasticity the boot needs to flex without cracking at the fold points. A boot that feels supple in warm weather may crack during a cold-weather work session when the rubber is at its stiffest. On the Bigbear 350 4X4, a boot failure at any of the four positions means grease loss and contamination entry that begins wearing the joint behind it from the first ride after the tear.
As a 4WD machine, the Bigbear 350 4X4 drives both the front and rear wheels. CV boots are present at both axle sets—two boots at the front and two at the rear. All four positions should be inspected and serviced together whenever one is found to be damaged.
How to Recognize Boot Problems Early
A failed CV boot on the 1987 Yamaha Bigbear 350 4X4 announces itself through grease on nearby components before it causes audible symptoms. When a boot tears at the front axle, grease from the rotating axle lands on the inner wheel face, the rotor, the caliper, or the front frame near the axle. A rear boot failure produces the same pattern at the rear wheel. CV grease is thick, dark, and adhesive—it doesn’t look like mud or road film—and it builds up with each ride after the boot tears. Any grease deposit in these locations on the Bigbear 350 4X4 warrants an immediate inspection.
Front boot failures on the Bigbear 350 4X4 often produce a clicking or popping noise during slow-speed turns under load—particularly noticeable at or near full steering lock. Rear boot failures more commonly show up as a clicking or clunking sound during acceleration or under load rather than during turning. Either noise alongside grease deposits means the joint behind the boot has sustained wear and needs evaluation alongside the boot replacement. With the wheel removed and the axle exposed, work each boot by hand while rotating the axle and look for tears, cracks, stiff fold areas, and gaps at the clamp edges.
On the Bigbear 350 4X4, all four CV boot positions—front inner, front outer, rear inner, rear outer—use the same inspection and replacement process. Check all four when servicing any one of them.
Tool and Parts Checklist
Stage the following before working on the 1987 Yamaha Bigbear 350 4X4: floor jack and jack stands; axle nut socket in the size correct for the Bigbear 350 4X4; torque wrench; snap-ring pliers; boot clamp tool; and shop rags. A separate CV boot kit—boot, two clamps, and CV grease—is needed for each axle position being serviced. CV grease is engineered for CV joint contact conditions and is not substitutable with off-the-shelf lubricants. The molybdenum compound in CV grease is what provides the film strength the joint needs under load.
Set a drain pan under the work area before starting disassembly. MotoSport.com carries CV boot kits and replacement axle assemblies for the Bigbear 350 4X4.
Wheel and Axle Removal Steps
Get the 1987 Yamaha Bigbear 350 4X4 on jack stands and remove the wheel from the side being worked. Remove the cotter pin and axle nut. Push the axle spline inward to free it from the hub, using a hub puller if the Bigbear 350 4X4 requires it. Release the snap ring at the differential inboard end and pull the axle free. Set it on a clean surface, cut the old clamp bands, and slide the torn boot free. For the front axle on the Bigbear 350 4X4, check whether tie rod or steering component clearance is needed before pulling the axle. Clean the clamp groove areas on both the shaft and housing before fitting the replacement boot.
What to Check in the CV Joint
Clean the CV joint on the 1987 Yamaha Bigbear 350 4X4 after boot removal and work it through its full designed articulation. Smooth motion throughout indicates a serviceable joint. Roughness or catching at any angle points to ball or race wear. Test for play by stabilizing the shaft and pushing the outer housing side to side and along the shaft axis. A healthy joint on the Bigbear 350 4X4 is firm in its articulation range with no rattle or looseness outside it. Play or clunking in non-articulating directions means the axle assembly needs replacement—sealing a worn joint behind a new boot produces a short-lived repair.
Boot Installation and Clamp Work
Before repacking the joint on the 1987 Yamaha Bigbear 350 4X4, remove all old grease and contamination from every internal surface. Thread the replacement boot onto the shaft before reconnecting the joint end. Pack the CV grease from the Bigbear 350 4X4’s kit into the joint completely, rotating the housing for even distribution. Use the full kit quantity. Position the boot with both ends seated in the clamp grooves, crimp both clamps to full engagement, and tug each to confirm it’s locked. MotoSport.com carries CV boot kits for this ATV.
Axle Reinstall and Test
Seat the inboard axle end in the differential on the 1987 Yamaha Bigbear 350 4X4 until the snap ring clicks into place—a pull test should show it locked. Guide the outboard spline into the hub, install and torque the axle nut to the Bigbear 350 4X4’s specification. Secure with a new cotter pin or re-stake as appropriate. Reinstall the wheel and torque the lug nuts. Lower the Bigbear 350 4X4 and steer through lock-to-lock range to verify the boot clears all surrounding components. A short test ride completes the service. MotoSport.com carries CV boot kits and axle assemblies for this ATV.
Related Shopping Categories
Shop CV Joints for a 1987 Yamaha Bigbear 350 4X4 ATV.
Shop Axles for a 1987 Yamaha Bigbear 350 4X4 ATV.
Shop Lubricants & Solvents for a 1987 Yamaha Bigbear 350 4X4 ATV.
Shop Wheel Bearings for a 1987 Yamaha Bigbear 350 4X4 ATV.
Shop Skid Plates for a 1987 Yamaha Bigbear 350 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.
