We are looking for an opinion on the following:

Issue: Are stored auto parts excluded from coverage by the policy?

FOL: Fire loss to unscheduled other structure. Although the insured did not include them in his contents inventory, he informed the field adjuster that he lost a lot of expensive car parts.
Relevant policy language:

Property not covered. We do not cover:

4. motor vehicles or all other motorized land conveyances. This includes:

a. their equipment and accessories; or
b. any device or instrument for transmitting, recording, receiving or reproduction of sound or pictures which is operated by power from the electrical system of motor vehicles or all other motorized land conveyances, including:

i. accessories or antennas; or
ii. tapes, wires, records, discs or any other media for use with any such device or instrument;
while in or upon the vehicle or conveyance.

We do cover vehicles or conveyances not subject to motor vehicle registration which are used to service the Described Location, or are designed for assisting the handicapped.
Interpretation of policy language: (Policy is attached)

Motor vehicle equipment and accessories are excluded from coverage, per the policy language. The phrase limiting the exclusion to “while in or upon the vehicle or conveyance” applies to b only. If it were meant to apply to both a and b, the indention would be to the left more. The definition of “motor vehicle equipment” is, “any system, part, or component of a motor vehicle as originally manufactured or any similar part or component manufactured or sold for replacement or improvement of such system, part, or component or as any accessory, or addition to the motor vehicle, and any device, article, or apparel not a system, part, or component of a motor vehicle (other than medicines, or eyeglasses prescribed by a physician or other duly licensed practitioner), which is manufactured, sold, delivered, offered, or intended for use exclusively to safeguard motor vehicles, drivers, passengers, and other highway users from risk of accident, injury, or death”.

Our Conclusion: Based on the information above, vehicle parts as well as motorcycle helmets are excluded from coverage.

California Subscriber

You are correct in that the exclusion for motor vehicles includes their equipment and accessories, as well as devices for transmitting, recording, receiving sound or pictures and related equipment and that the two clauses act independently.  

However, the policy has no definition of "motor vehicle equipment" so I'm not sure where you got that - it's not in the policy, and therefore does not apply. When terms are not defined in a policy, standard practice is to use a common desk reference. Merriam-Webster online does not define motor vehicle equipment. Equipment is defined as "the set of articles or physical resources serving to equip a person or thing". This is a broad definition, but the exclusion is equally broad. Therefore, anything that could be considered equipment for a motor vehicle would be excluded. 

Helmets are a different thing though - they are apparel, not equipment for the vehicle per se. Granted, they are for the safety of the rider, but they do nothing to or for the vehicle itself. You could use your motorcycle helmet to engage in other not so safe activities - its purpose is to protect the person wearing it, it does not equip the vehicle in any way. You can also ride the motorcycle without wearing the helmet - in many states it is optional. I would cover the helmets.