It's not worth involving lawyers unless there is an injury.
Have you checked around for a used one and found one? If so, that is a starting point as to it's present value. They may even buy the used one you or the adjuster found just to settle the claim.
Remember, the burden of proof is on you.
LKQ-- Like kind and quality-- Prior posters are correct. If there is no "benchmark" than we must look at something of equal like kind and quality to get a ballpark value whether new, subject to depreciation, or the actual used price.
After a value is established and all liability issues ironed out they will make an offer. If you are in a comparative negligence state and you are found partially to blame they may deduct a percentage of the payment.
Any adjuster with a big case load wants to get rid of the nickel and dimers asap.
They can be flexible with a case like yours to a point because again, no benchmark but they have bosses who review files and have to justify their actions.
Under certain cicumstances they may let you keep the bike because it is more trouble than it's worth to get bids on it for salvage.