Checking valve clearence -

-KTM engine blocking tool in case you need to change your shims, it's a lifesaver: 0113080802
-A Harley Davidson dealership for shims
-A torque wrench
-A 90 degree torque wrench tool for the rear cylinder exhaust cam retainer bolts
-A very thin walled spark plug socket, that or one from an EXC if you don't have one.
-Some string/twine to hold the radiator/oil tank
-A magnetic pickup tool to get the shim buckets up if you need to change the shims
-A pad of paper/pen to mark the tolerances of all the valves
-A micrometer to measure the shims

And some patience doing it your first time around, I think I spent about 8 hours or so. After doing it and seeing how easy it was it should take me less than 4 hours to do now(especially seeing how i ripped out the SAS junk).

Note: The service manual shows the picture of the adventure motor, the 990 SD cam gears have dots instead of cross hatches that line up with the top of the cylinder head. The latter are also only really needed if you change your shims, you'll be ok with them there if you're just checking them. I have to swap out 6 shims.

I pulled the tank, airbox, throttle bodies, radiator, and oil tank to make life easy as i was doing an oil change and replacing my radiator fluid with water/water wetter. You may not need to pull your radiator or oil tank but you should probably unscrew them and hang them out of the way so thatyou have a little more room on the front cylinder.

Also, if you're going to swap shims you may as well measure all tolerances and the shim thickness of every valve, that makes it much easier next time around as you'll know your wear (tolerances) and valve shim size.

Some links that may help:

i'll second trackadict, can we have this moved to 'how to' section? this is very usefull