Can I deduct expenses related to the use of my scooter, (basically a motorcycle), for food delivery for Caviar? My expense was mainly fuel, but I also have miles driven.

You can't use the standard mileage method since that only applies to passenger cars.  You can use the actual expense method.

1. Keep track of all your mileage (business and non-business) for the year, so you can determine the business percentage.

2. Keep track of all your expenses (fuel, maintenance, insurance, depreciation), and you can deduct the percentage equal to the percentage of business use.

If audited, the IRS does not have to award expense deductions you can't prove with adequate records, so if you have been doing this for a while and not keeping adequate records, you may be in some difficulty.  Saving all your receipts is not strictly necessary but you need some kind of contemporaneous record listing the expenses, as well as the business mileage (date, mileage and business purpose).  If your records are made up long after the fact from memory, the IRS will be less likely to accept them.