Do you plan on running another crew in the near future? Hold onto it.
If not...Is your bc1500 under warranty? If so I think I'd sell the bc1400 if I were in that position.
But the decision to sell depends on your business model.
Do you already have all the trucks and equipment you need? If so, then the 1400 is a good backup, and you know the history and/or quirks the machine you have, as opposed to buying another used machine.
OR could the money from selling the bc1400 get you into (or closer to) another truck, grapple truck, bucket, grinder, loader, etc.? That you would use more and could make you more money than the bc1400 that is only sitting.