xt600 has dry-swamp-lubrication system (i'm sure this is not the correct english but i don't know better. hope, you know what i mean).
ALWAYS check the oil level after driving at least 15 km:
let the engine run idle for about a minute in vertical position, then stop engine and check oil level.
if the engine is cold and you are not sure about the amount of oil, check oil level first:
if level is below minimum on dipstick, fill up first to minimum and then proceed as described above.
if neccesary, fill up then to maximum.
it is normal for xt600 that there is no or few oil in the oil tank if the bike wasn't used for some time.
yes, you can have both!
you can use the kick starter and decompression unit from an earlier bike. in addition you need some minor parts, 2 oil seals, 1 bolt for the kick stater spring
and 1 guidance ring to be mounted in the right engine cover on the kick starter axle boring.
some pictures you can find here: http://www.xt600.de/xt_schraubertips...rter/index.htm
(click on 'bild')
i'm sorry, but i cannot translate all this to english, no time!