Yep. What Michael said. Spend some time cleaning out the fuel tank and petcock screen. Maybe new fuel lines. Drain and replace lubes in the engine, transmission, driveshaft and final drive. Flush the brake fluid, too. Add front fork oil drain and replacement, too.
Other items that may need inspection and/or service are wheel and steering bearings, brake pads and shoes. Air and oil filters.
You know the tires are at least 13 years old. They will have a 4-digit code on the sidewall -first two digits are the week and last two are the year of construction.
Take the time to insure the bike is in safe working order. Better now than after an incident.
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