Converting a CT to 12 volts
It's possible to convert your CT's electrical system to 12 volts. Why would you want to do this? First, 12V accessories and lighting are easier to find, since almost all cars now use 12V. Second, 12V lighting is likely to be brighter, making you more visible in traffic and giving you longer headlight range at night. 12V ignition may also offer better performance and reliability.

One listmember went ahead and did the research on it and used his own bike as a guinea pig:

All,

After a lot of work and experimentation I've finally rewound the CT-
90's alternator armature to be "optimized" for 12 Volts (actually
14.5V). The stock armature has 6-poles, four of which were dedicated to
the headlight circuit and two poles dedicated to the ignition circuit.
The stock headlight circuit had a total of 48 feet of 18 gauge wire (or 12
feet per pole). The stock ignition circuit had a total of about 480 turns
of 22 gauge wire or 240 turns/pole (I did not measure the length).

After rewinding the alternator a first time (i.e. I wound 26 feet of 18
gauge wire on all six poles for a total of 156 ft.)and after a lot of
testing with various resistive loads found that it was "optimized" more
for a 40 Volt system, I re-calculated that each pole should really have 11
Feet/pole of wire for a total of 66 Ft. over six poles. I also used 14
gauge wire instead to decrease the resistive losses.

Last night I hooked this second version of the rewound alternator to a 55
Watt Halogen and blew the filament. Did the same with the 65 Watt
filament.

So if anyone out there would like to convert their bike to 12 Volts
to boost their headlight wattage from the 25 Watt stock set-up to 55 W at
3000 RPM, here are the details of what I did:

1) Soak armature in "paint/epoxy remover" to get rid of the old epoxy;

2) Remove the existing wire from all poles;

3) Add new epoxy over any exposed metal on the poles, such as "Flame
Retardant Potting & Encapsulating Epoxy Compound 832-FRB" from MG
Chemicals see ... http://www.mgchemicals.com/products/832frb.html

4) Wind Eleven Feet of 14 gauge "magnet wire" such as "HPT —
Heavy
Poly-thermaleze Class F, Type T-2" available from Allied Electronics at
... http://www.alliedelec.com/catalog/pf.asp?FN=118.pdf. It is VERY
IMPORTANT to wind exactly eleven feet of wire on each of the six poles as
this will maximize the armature's Wattage for 14.5 Volts. Each pole MUST
BE alternately wound in a "clockwise" and then "counterclockwise" manner.
See the following web site for more information on how to do the winding:
http://www.suzukicavalcade.com/Maintenance/stator.htm

5) Recoat the wound wire with the epoxy again.

And you're done!

I still have to test what the maximum amperage out of this will be. I've
calculated about 7 Amps at 6000 RPM and 13 Volts. But overall the newly
rewound alternator should put out about 70 Watts at 3000 RPM and 95 Watts
at 6000 RPM.

Of course you'd also need to "mount" the new Halogen on the bike,
convert the ignition system to 12 Volts, change all the bulbs, and
replace the 6V batter with a 12V one (J.C. Whitney show a "Power Max" one
in it's catalog that seems to fit the CT-90's current battery housing.

The above information was hard won and took me the better part of six
months to do the research and find the parts, and then take the "dive" and
destroy my current set of windings in the hope that it would all work out,
but after making a mistake on the first re- winding attempt, the second
one seems to be on the money. So enjoy!!

A 55/65 Watt puppy in the woods or on the road should really brighten the
trail and/or make you more visible to traffic. :)


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Last updated: 05/11/2003