From my experience with badly starting XTs, please check / do the following first:
1. Adjust the idle mixture correctly. The standard factory setting will not work for your older bike. Warm up engine, screw out idle screw till engine speed increases, keep screwing out till engine speed starts decreasing again. Leave it there. You'll find that you'll need 4 maybe six turns out.
2. Adjust deco cable correctly (just to make kicking easier). With running engine, push level on cilinder head backwards, you'll feel the exhaust tappet at a certain point. The play in the cable should be approximately 1 mm, not more.
If the above does not work, try the other suggestions.
You cannot use the data from the TT600 2004 handbook - the ignition system is different. For correct data, check here, use translator if required:
Wartungsdaten XT600-Modelle.
You can assume that the CDI is OK, in fact I have yet to see one go bad.
The electrical power for the ignition comes from the alternator, not from battery.
Good luck!