I know there are several to choose from. I just did mine on my new to me 99 tourer with cobra exhausts. The drain plug is very easy to get to. The cobra exhausts are right in the way of the refill bolt. I was able to access it by removing the RH saddlebag (4 bolts 8mm inside the bag. Only takes 5 minutes to remove) After removing the refill bolt (just above and left of the drain bolt) I put a piece of left over fuel line on the tip of the Lucas synthetic 75-90 bottle and was able to easily get the fuel line into the refill hole. Fill up level with the bottom of the hole with the bike sitting up straight, Reinsert the fill bolt, reinstall the saddlebag and done. Like someone posted earlier, don't over think this, it is a pie job.
Thats a very fine way of changing the final drive oil for those that never take the final drive off the swing arm. Just beware never greasing the driveshaft may leave you stranded someday.
