If you benefit from itemizing deductions, you can deduct the portion of the value of the stolen property (less $100) that exceeds 10% of your AGI.
So, if your AGI is $50,000 and you itemize deductions, you can claim a $1,600 deduction on the theft. If AGI is $66,000 or higher, no deduction, if $40,000, a $2,600 deduction, and so on.
IRS Form 4684 is used for this.
The starting figure is based on fair-market value at the time of theft, so if you put considerable miles on the bike in 5 months or if demand has waned, it may be lower than purchase price. You can also add in cost of personal items that were on the bike, you subtract $100 from the total cost of the incident, not from each item.