Motorcycle Repair: 74 Yamaha Dt250- Electrical Questions, regulator rectifier, yamaha dt250

Question
Boy it looks like you stay pretty busy answering people's questions. Well
anyways, I have a 1974 Yamaha Dt250. I've gotten most of the electrical
issues I was having sorted out (knock on wood) but I still have some
questions. First off when my motorcycle is running at idle with a good
battery, the battery shows about 8 volts. Is this normal good charging voltage
for a 6v system? Also my turn signals don't blink they just stay lit solid. I am
assuming the flasher relay needs to be replaced? Also my horn is real iffy. I
know its getting 6v but it only works good off and on. I found a new horn for
$9, should I just replace it? Last question. My headlight circuit looks like its
putting out around 8v ac at idle. Is this too much? I don't want to risk blowing
any bulbs, especially the headlight because they expensive. I found a voltage
regulator/rectifier combo that will work for my bike for about $30. I really
thought that it would be a good investment to install one, so I was just
wondering what you thought about them, such if they are necessary or not.
Thanks so much for your help!- Matt

Answer
Matt,

I do put alot of time into finding answers that
will help.

-Your battery voltage sounds about right for a 6 volt system.
(A standard output might be about 7.7 volts at 4000 rpm)

-if the signals don't flash, it may be the flasher
or the wrong bulbs. You likely will need a 6 volt flasher
of some kind. Make sure the bulb sockets are not
corroded.
-the horns never did work well, even when new.
A replacement might be good, 6 volt also.
-these bikes use a balanced charging system,
that means the battery, headlight, speedo/tach lights and taillight
need to work or the voltage can spike, which
can burn out headlights.
-For example, if your taillight burns out
or your speedo/tach lights, then the voltage
goes up and soon burns out the headlight.
Same thing if the battery is disconnected for
any reason.
-Later bikes like the 75 DT250B or such had a little
regulator that controlled the charging voltage.

http://www.cmsnl.com/yamaha-dt250b-1975-1976_model8548/partslist/F-05.html

-So it might be a good investment to look into
some kind of 6 volt regulator to save headlight
bulbs. The headlight can likely handle 8 volts
but not any higher.