i couldnt find anything on this so i thought i'd post something in case anyone else is as clueless as me with electronics. if you have a CDI and want to check your timing, heres some info.
if you already shelled out $150 for that CDI kit you can afford to go to harborfreight.com and spend $12.99 on a timing light break>
you'll also need either a 12v car battery or one of those car batter chargers, which is what i used.
i was setting the timing on my minarelli, which is great because there are already hash marks on the magneto indicating where TDC and 23 degrees before (2mm) are. there is also a little notch on the case to use as a reference point with the aforementioned hash marks.
if your bike doesnt have these markings, you can make them yourself - one on the case for reference, then mark TDC on the flywheel, as well as whatever point before TDC you want to run, depending on whether you want to retard your timing or maybe run it all hella advanced like those crazy west coasties.
next you want to hook up the timing light to the battery, red to red, black to black. then there will be another wire off the timing light, the induction clip, which you just clip around your spark plug wire. your plug stays right where it is, as if you were running the bike normally, you just clip the thing somewhere along the wire.
go ahead and start the bike, then simply point the timing light at your markings on the magneto. it will flash exactly when the spark is happening and you should be able to see if the markings you made are lining up. if not, move your stator plate accordingly and try again.
super easy. screw points. CDI FTW.
if this is all old news sorry for being redundant, but i didnt have any clue what i was doing and i figured someone out there might need the help.