This procedure is the same regardless of which of the above twisted twins you have; the layout of the three ports is the same on each.
These photos have been done with the wheel removed, however it can be done with the wheel in place or removed.
Note – the final drive unit does not use engine oil! 80w90 gear oil is suitable. Make sure it says it’s for hypoid gears.
Final drive unit – breather on top, filler/inspection hole on the left and drain hole at the bottom:
Bucket or other container underneath – it doesn’t have to be very large, as you won’t get a large volume out of the final drive:
These aftermarket exhausts only just allow clearance for a socket to get through. Remove the drain bolt with a 10mm socket:
Loose, not yet removed:
Removed, draining:
Leave it for ten minutes to fully drain, then re-insert the bolt and remove the inspection cover with a 17mm socket/wrench.
*photos coming*
With the bike on the center stand or level, pour the new oil in until it is about to flow back out the inspection cover hole – that’s the correct level.
*pic coming*
Replace the inspection cover, and job done!