I have a 1979 dt175. Bike does not have an any working lights so I’m looking to add this back on and get it road legal after I confirm it’s registerable. In looking at replacement parts there’s more options for 12 v for sure. I’d prefer to keep the bike OEM so sourcing 6v parts looks to be a challenge. I do not want LED.  Curious why guys switch working 6v systems to 12 v on working bikes? Is it mostly to switch from magneto to CDI? I’ve done a forum search and that seems like the biggest reason.

I converted a 12v system back to 6v....

If you have a 79 175 you are already on CDI and ignition system is completely independent of charging and lights.

Availability #1

cliff

I have been considering it on my 75 DT 175B mainly because the brake and taillight are not very bright. I'm afraid the someone will run into the back of me. Also the blinkers barely blink. I have all of the correct bulbs in it. I am guessing this would help. The Vape system has a 180 watts output for the 175, I don't know what the stock is, but I don't believe it is very high.

Jim, it's possible your dim lights can be improved greatly by maintenance...  brake and tail are both run from the battery so the "output" of the stator is not going to be the cause of dim lights unless the charging system can't keep up and the battery is losing charge over time. 

If lights are dim all the time, even with a good battery that's charged, you will probably measure a significant voltage drop from the battery to the bulbs.  Corrosion in the connections and switches and sometimes corrosion inside the harness wires can really cut down on the power that gets to the bulbs. 

JIMA, I've replaced the taillight bulbs on my CT1-B with 6v LED bulbs which run a lot brighter.
My CT1-C has LED bulbs throughout fitted to the original holders and I replaced the headlamp bulb in the sealed unit with an LED.
All the info is is on the forum.

LED bulbs draw a lot less current so the affect of resistance in the connections, switches, and wires is greatly reduced. 

@Pete I'd be really interested if you have a post / links about your 6v LED's (most of the new ones are all easy install (no fussing with diodes) for a DT125 air cooled (that is if I ever get a hold of it, looking at July right now)

Interesting. Thanks for the replies. So there doesn’t seem to be a real strong case for someone like myself that had CDI already. Sounds like I’ll save the expense of the conversion only to pay later in having to possibly pay more for 6v lights later. 6v bulbs do not seem to be overly pricey. I’ll stick with 6v for now.
One question though. If my CDI fails would this be a reason for guys to switch over. Are 6volt CDI’s hard to source?

Not that hard to source.  Note that the 78/9 CDI box is different from the 80/81 box because the 78/9 model has an extra source coil..
78/9 box has 7 wires.  Later types have 6 wires.

These CDIs are pretty reliable.