Final Drive Unit Oil Change - Drain Plug Size

[growler]

Had a heck of a time trying to get the drain plug loose to change the final drive unit oil.

In the tutorial it states it's the same as a spark plug socket, but the socket I have is too deep and isn't grabbing right. I don't want to strip the nut, and all the other sockets I have aren't large enough. Is it 18mm?

Many thanks.

[GSX1000E]

The fill plug is 17mm and the drain plug uses a 21mm socket. I prefer to use 6-point sockets exclusively.

[growler]

awesome, thanks!