The drive pulley bolts on the snowmobiles can break due to oil contamination during the assembly process. This can cause debris to come off the vehicle and act as projectiles, posing a laceration hazard to riders or bystanders.
The rear axle bearings may have not been sufficiently greased. This may cause a breaking of the bearing, which could make the ATV unstable. The operator could lose control of the vehicle, which could cause injury to the operator.
Inappropriate clutch ring gear installed on some units. This may cause ring gear fragmentation at high speeds and debris could act as projectiles. A projectile could cause serious injury or death.