Forum

[wetdog]

I am still putting the lights on my GT and now know the plugin headlight is correct thankyou . my next Q is where any of these GTs 12 volt ? there is a zena fitted now and the original loom is here with the large spade to fit the same , the only information I can find says the GT is 6 volt is this correct ? fitted to the bike now is all 12 volt inc battery , coil etc

[Mark M]

No 12 volt Continental GTs as standard. The Factory offered a 12v option on the 750cc Interceptors for 1965-66 though so maybe someone has transplanted one. Or fitted later kit.

REgards, Mark

[John M]

I wouldn't think that it would take much to convert to 12 volts, assuming that it uses a 3-wire Lucas alternator. All you need is a modern voltage regulator, new battery, bulbs and coil. As I understand it the 12 volt alternators are similar to the 6 volt alternators, but the 6 volt systems used a complicated method of switching the pairs of alternator coils to avoid over charging, where the 12 volt system uses all six coils as modern voltage regulation is more efficient than the old methods.

[Mark M]

The original 6 volt system on the GT is very crude, there is no voltage regulation at all, just a rectifier. Excess current simply boils the battery giving it a really hard life. I run mine with at least the pilot light on to try and soak up some excess. The 12 volt systems of the time are a little better as they use a Zener diode mounted on a heat sink, converting excess current to heat. It's still a poor way to treat the alternator, effectively running it flat out all the time. A modern voltage reg/rec is a worthwhile improvement without doubt. Note also that the 1960s 250s use a smaller diameter alternator rotor and stator than the bigger models. And very early 250s have an even smaller one so if uprating to 12 volt it's worth changing the whole lot!

REgards, Mark

[wetdog]

its 12 volt now and has been run like this for many years without lights , the problem has come as now I intend fittings lights and putting the original harness back on (plug in light etc) the original harness has the zena spade conection and the zena is fitted to the bike now but all information says 6 volt , I donot want 6 volt but why has the harness a zena conection ?

[Bullet Whisperer]

If the switches and charging system are wired correctly on a 6 volt system, the battery will not boil, as only two alternator coils are 'on' with no lights, four with sidelights and all six come on line only when the main lights are switched on. 12 volts from a 6 volt alternator is easy, just connect the dark and mid green together, treat as one wire and leave the light green on its' own and then stick them into the two yellow wires of a Boyer Powerbox and you will have 12v DC coming out to power whatever you have / need.

[Mark M]

Paul, you're right, I was trying for comedy. "Overcharge" would be a better description! The load balancing is very imprecise and over charging is a regular problem (or was when these bikes were being used hard). I think that's why so many of the GT electrics plates and battery boxes are rotted by acid spills. That and carp maintenance by 17 year olds! By the way, I had a go on a 350 New Bullet (Crusader) the other day and really enjoyed it, what do you think, from riding and working on one?

REgards, Mark

[wetdog]

this one best stay 12 volt I think as it sounds like an improvement over standard

[simon]

I put a Pazon 6v regulator/rectifier on my 350 and it has lovely bright lights and a battery that doesnt get any more than it needs. Its a fully reversable mod that involves wiring the alternator for maximum output and by passing all the switched variable output gubbins. Everything else stays the same.

[wetdog]

can anyone tell me the exact position and location for the rear brake light switch for this bike please