Or do you need speacial tools?

You sort of need special tools, depending on the variety of lefty, although I always managed to service my 2 leftys at home without a problem.

You can do minor preventative maintenance at home v easily – stuff like bearing resets, air filter clean, grease the internals etc. This will keep it ticking over no problem.
There are instructions on line for a full on dissasembly and oil change which seem fairly involved and do require a special ‘castle’ tool. Never been arsed to do this myself, but would probably be fine if you have a fettling frame of mind.

If you have the castle tool it’s easy to service the cartridge, all you need is a park pin spanner and some fresh oil.If you do though, be careful not to knock the race retainer clip off the slider. It’s fairly easily done and can be a PITA to pop back on properly.

A mate has asked me to service his Lefty’s (seeing as I like fork fettling and he doesn’t!) – however, I have no previous experience with the Lefty at all. Am I just getting involved with a load of hassle….? Plenty of experience servicing various Fox and RS forks and shocks, but the Lefty is quite a differant beast!

I used a park tools flat ended pin spanner in place of a ‘castle tool’:

http://www.parktool.com/product/pin-spanner-yellow-spa-4

Works for the old dlr2 cartridge, not sure about other versions.
Don’t think the lefty max needs a castle tool if irc.

Ahh, does that get into the cartridge? I have an old ELO so have the big 2 piece castle tool for that. Works for headshoks too.

Don’t recall having to use a castle tool for the coil sprung lefty’s. The dampers were in the base of the leg. (although my knowledge of that is limited to the 140 FFD)

Theres lots of info on servicing Lefty’s on the Cannondale MTBR forum