Replacing old 6v headlight bulb w/modern brighter bulb

In article <MaCdncCNMZcD-9bVnZ2dnUVZ_h_inZ2d RemoveThis @giganews.com>,
"David T. Ashley" <dta RemoveThis @e3ft.com> wrote:

> "Timberwoof" <timberwoof.spam RemoveThis @infernosoft.com> wrote in message
> news:timberwoof.spam-6BCF72.12372607062008@nnrp-virt.nntp.sonic.net...
> > In article
> > <d67d7cba-8f50-44e2-ad33-d85870b54e3c RemoveThis @d19g2000prm.googlegroups.com>,
> > Rob Kleinschmidt <Rkleinsch1216128 RemoveThis @aol.com> wrote:
> >
> >> On Jun 5, 5:28 pm, "David T. Ashley" <d... RemoveThis @e3ft.com> wrote:
> >>
> >> > Unless I missed an obvious product, looks like you're stuck with a 6V
> >> > bulb.
> >> >
> >> > Converting from 6V to 12V DC requires a device a bit more complicated
> >> > than a
> >> > transformer.
> >>
> >> Seems like you could almost do the whole electric
> >> system with a device no more complicated than a
> >> transformer if the bike was powered by an alternator.
> >>
> >> Put a transformer between the alternator and the
> >> rest of the bike and swap out 6 volt for 12 volt
> >> horn and bulbs.
> >
> > The only problem is that the alternator is probably three-phase; this
> > makes finding the right transformer tricky. An alternative would be to
> > rewind the alternator with wire half the cross-section but twice as many
> > windings ... and then put in a new rectifier and voltage regulator.
>
> It has been many years since I studied 3-phase power, but I think you may be
> able to make a competent 3-phase transformer using three single-phase
> transformers where you connect the inputs in the obvious way (A/B, B/C, and
> C/A), then connect one wire of each of the outputs together and use the
> other 3 wires.
>
> That is just a hunch. I think that will give you 3-phase power at a
> different voltage.
>
> However, I don't know how you'd rectify the voltage. With single-phase
> power, a full-bridge rectifier and a capacitor will do it -- not sure what
> to do with 3-phase.

Same way as before: the three coils of the alternator are either in a Y
with the center being ground or in a delta. Now consider the diode
bridge for an ordinary one-phase center-tapped transformer: basically
each outer end of the transformer has two diodes, one this way and one
that way. So you add two more diodes for the third leg of the Y. If it's
a delta, then it works the same way, only there's no "center tap".

--
Timberwoof <me at timberwoof dot com>
faq: http://www.timberwoof.com/motorcycle/faq.shtml
Ten Steps to Fascism: http://www.guardian.co.uk/usa/story/0,,2064157,00.html

Thank you all for your replies. I'm looking at the simplest alternatives.

I'm going to order a modern rectifier. I'm going to let this gentleman send me a rectifier ready to plug into my bike.

http://cgi.ebay.com/ebaymotors/Rectifier-CB-CL-XL-CT90-100-125-175-250-350-360-450-500_W0QQcmdZViewItemQQcategoryZ35594QQihZ011QQitemZ320266142658QQrdZ1QQsspagenameZWDVW (http://cgi.ebay.com/ebaymotors/Rectifier-CB-CL-XL-CT90-100-125-175-250...0-360-4)

I'm also going to take a look at the reflective lining inside the fixture to see if it can be cleaned or somehow re-lined.

This bike sat ouside under a roof for 21 years before I got it running and road worthy again. Part of that process was checking, fixing, disconnecting and cleaning every electrical wire and connection.

During the restoration I sanded, primed and re-painted the entire frame. One of the problems I had with the lighting system, especially the turn signals is with grounding. Instead of each light fixture having a ground wire, the fixture itself is used as the ground at the point where it contacts the frame of the bike. The newly painted frame greatly hindered the grounding effect.

I used a little solder to improve the gounding points but I will sand off some paint to the bare frame and re-solder to make sure I have a good ground connection. Hopefully this step will improve my turn signals to give me a more consistent blink in my blinkers and possibly give me a brighter head light.

Thanks again for all of your input. Some of the advice is more complex than what I'd like to do now, however it's good to at least think about my options for the future of this bike.

Here is the website for Oregon Motorcycle Parts where I ordered the rectifier. He will add the proper wiring and connector plug. At the bottom are some customer feedback remarks.

http://oregonmotorcycleparts.com/AboutOMP.html