Could anyone recommend me a good video?
Also, I have a 2018 Evol fork - do I just need any NA2 shaft of the correct length?
They don't come in Evol and non-Evol variants, do they?
https://www.ridefox.com/fox17/help.php?m=bike
Stick the 4 digit code in the Fox site, it should tell you exactly what you have and hopefully link to service procedures, if not knowing what you have you can then find the correct service procedures and parts list. Check the damper you have fitted is compatible with the new air shaft.
Well that's shed some light on the matter, thanks - but still not crystal clear and Fox's details are not exactly user friendly.
One type of airspring for 34 factory/perf/perf elite.
A different one for rhythm.
Air Spring replacement is same as for 36.. lots of vids but you need fork grease and 20w gold. No special tools required, just patience to work the retaining ring out and back in.
Oh yeah, don't forget to depressurise first.
If you phone Silverfish with the Fork ID code and tell them what you want to do they are normally very helpful with part numbers.
If you post up more info, fork ID code or exactly what you have people on here may be able to provide more help.
NA2 air shaft service;
32/34 instructions with pictures
https://www.ridefox.com/fox17/help.php?m=bike&id=616
36 video
https://www.ridefox.com/fox17/help.php?m=bike&id=845
2018 34 parts
https://www.ridefox.com/fox17/help.php?m=bike&id=860