Converting an Alternator system from 6 to 12V
If your bike has a Lucas 6V 3 wire alternator system, with a simple wiring change it will be able to power a 12V system.
Disconnect the Green/yellow alternator wire from the loom and join it to the Green/black alternator wire. That's it. The job's done.
The 3 wire alternator is only 100W max. so will be OK for points ignition but won't run a Boyer ignition with your lights on for long.
The existing 6V rectifier will be OK, but you need some form of Voltage control. Fit either a Zenor diode (£19.95) or remove the rectifier and fit a regulator/rectifier unit (Power module) (£29.95) These are more reliable, more efficient and easy to fit.
If you have a single coil ignition fit a 12V coil. Or for twin coils 2 x 6V coils can be wired in series. £15.50 ea. A dtwin output coil can also be fitted to a 6V or 12V system. £29.95
A 6V horn will be OK,but will sound louder.
Obviously you will need bulbs. If you've fitted a new alternator a 60/55W headlight bulb will be OK and give you a light as bright as a cars. If you're sticking with the old alternator a 60/55W will probably be OK, but a 35/35W is guaranteed. £8.25 for British Pre-Focus.
Tail light, standard 0.60P. Much Brighter Quartz Halogen £7.50. Brighter with low current LED £12.95
Speedo light 0.60P
For the battery, measure up for the largest battery that will fit.
|This is a diagram of a basic 6V system converted to 12V using a Zenor diode for Voltage control. The wiring details of the more modern regulator/rectifier conversion are above.|
|Courtesy of the most marvellous old bike magazine in the whole wide world at www.RealClassic.co.uk They're modest as well.|
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