Part of the routine service schedule for any shaft drive motorcycle including my 2014 Yamaha FJR 1300 ES is changing the final drive oil. This couldn’t be any easier, it’s removing two simple bolts, changing two washers on them, draining and refilling a tiny bit of oil. This is a relative long service interval maintenance item, but it is done very early in a new bikes life as part of the break-in service. Don’t spend hundreds of dollars at a dealer, nothing is hard to do for this kind of work. The oil is a bit pricey but not when you consider how many years a bottle lasts. For this you just need the oil, a ratchet and socket, an oil pan and some aluminum foil to contain the mess.