And the front? If you insist:
Remove the front wheel, mudguard, brake calipers and ABS sensor - basically all the screws in this pic (and of course the ones on the other side!):
Then loosen the top yoke clamp:
Now loosen - but don't remove - the fork leg cap, it's a 19mm spanner. You will not be able to undo it once it's off the bike.
Now loosen the lower clamp:
And slide the leg off the bike.
Get a suitable tub handy to pour the old fork oil in. Stand it on a big rag, (towel?) the oil gets everywhere when you remove the spring.
Undo the fork cap completely, supporting it as you do since there is a little tension from the spring.
Now using a 13mm spanner, undo the locknut so you can unscrew the fork cap from the damper rod. They're not particularly tight (20Nm).
Remove the fork cap - you can let the damper rod go. Extract the fork spring and let the leg collapse, but don't lay it down as it's full of oil still!
Up-end the fork and drain the oil from it - beware as there is a hole in the shiney bit near the fork seal when it's fully extended. There is also a spacer in the fork botom, which comes as a surprise since it's made of plastic!
Pump the damper rod a few times to work the oil out of the damping passageways. Hang the leg upside down over the catch tub while you do the same for the other fork.
Once both forks are draining, go for lunch. Make it a good long one, so all the oil is drained.
Rebuild time!
Add oil to the right level (110mm) BEFORE you add any of the components. Remember to pump the damper rod until you can no longer hear air gurgling.
Once you have the level right, drop in the spacer then the new spring - tight coils uppermost. You'll find it easier to pull the damper rod fully up before you fit the spring by the way.
Now using all three hands, stop the damper rod from retracting whilst you fit the top plastic spring locator over the rod, then screw the cap on. I found that compressing then bending the spring slightly held the damper rod in place.
Tighten the fork cap locknut (20Nm) and then the cap into the leg as much as it'll go - final tightening can only be done back on the bike.
Refit the fork to the clamps, ensuring the machined line sits flush with the top of the top yoke (5mm showing) and tighten ONLY the lower clamp to 19Nm.
Tighten the fork cap to 20Nm, then tighten the top clamp to 19Nm.
Refit the mudguard, then the front wheel - torque the wheel spindle to 30Nm
Torque the front spindle clamps (4 bolts at the fork bottoms) to 19Nm.
Refit the calipers, torque the bolts to 38Nm.
Refit the ABS sensor, torque it's bolt to 8Nm.
Spin the wheel, and apply the front brake. Happy?
Drop it off the stand and climb on. Ooh! You can touch the floor!
Cheers!