Author Topic: Dragonfly 12V conversion  (Read 538 times)

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Offline Sgtbiro

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Dragonfly 12V conversion
« on: 05 Feb 2020 at 07:35 »
Hi all what I would like to know is how easy is it to convert my Fly to 12v is it to difficult for  novice.

Cheers Kevin...

Offline Bynorthsea

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Re: Dragonfly 12V conversion
« Reply #1 on: 05 Feb 2020 at 17:28 »
It's relatively easy to fit a 12 solid state rectifier / regulator but don't forget every other  component needs to be uprated to 12v.

Offline Red

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Re: Dragonfly 12V conversion
« Reply #2 on: 05 Feb 2020 at 18:59 »
Hi Kevin

Please see below previous advice from Eddie on this subject:-

 You can convert to 12 volt using the original generator. I have a Special that uses the standard Miller generator wired to give 12 volt and incorporating a Zener diode to dump any excess voltage to earth. Although only rated at 60 watt, when set up for 12 volt, it gives in excess of 8 amps at 12 volt (96 watts). Of course, when operating like this, the generator is giving full output, so needs more power to drive it - not good when you have a Dragonfly with just 18 BHP!
     To get 12 volts, firstly replace the original rectifier with a modern solid state unit. The generator lead that went direct to the old rectifier should be connected to one side of the new unit. The other 2 generator leads that went to the lighting/ignition switch should be joined together and connected to the other side of the rectifier. The Zener diode should then be wired into the output side of the rectifier (to control the maximum voltage).

               Regards,
                         Eddie.

Offline Sgtbiro

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Re: Dragonfly 12V conversion
« Reply #3 on: 05 Feb 2020 at 19:56 »
Thanks guys a lot of useful information as I need all the help I can get once again many thanks.
Cheers Kevin.

Offline tck

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Re: Dragonfly 12V conversion
« Reply #4 on: 07 Feb 2020 at 12:51 »
You could also buy an Alton Generator its an alternator in a dynamo sized package comes complete with regulator I have asked Alton and the direction of rotation is not an issue I have two in use both on my Vincents and they work and look fine.

Offline Sgtbiro

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Re: Dragonfly 12V conversion
« Reply #5 on: 09 Feb 2020 at 11:00 »
Thanks for your reply tck the only problem i have is that were electrics are involved i don`t have the first clue i know very little, what i would really like is that if there was someone out there that lives close to me they could come and teach me some basic stuff, i live in Newcastle.

Cheers Kevin..

Offline tck

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Re: Dragonfly 12V conversion
« Reply #6 on: 09 Feb 2020 at 12:17 »
there is a wiring diagram here on this forum
https://www.douglasmotorcycles.net/index.php?topic=5615.msg20340#msg20340
the Alton comes with a wiring diagram

Offline Sgtbiro

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Re: Dragonfly 12V conversion
« Reply #7 on: 10 Feb 2020 at 21:29 »
I would also like to add electronic ignition to my Fly, So if i buy a new 12v coil rectifier condenser and bulbs what do i need to do to replace the contact breakers and distributor and how do i fit them, any info/advice would be gratefully received.

Cheers Kevin..

Offline tck

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Re: Dragonfly 12V conversion
« Reply #8 on: 11 Feb 2020 at 07:45 »
contact breakers and distributor do just that. Voltage in the ranges we are talking about dont matter

Offline Red

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Re: Dragonfly 12V conversion
« Reply #9 on: 11 Feb 2020 at 09:32 »
Hi Kevin

I must admit I took the easy option. Iíve had my Dragonfly for nearly 50 years, and it is still on 6 volts. I had problems with the ignition some 10 years back and suffered from a constant misfire and running on one cylinder. I thought about electronic ignition but decided it was too expensive. I ended up by fitting a 6volt twin output coil from a 1970ís Honda CD 175 which even today you can pick up new for less than £20 Ė see photo attached. Whilst the distributor cap and rotor arm are still fitted and these need to be left in place they are by-passed as the HT leads from the coil go direct to the plugs and the leads provided with the coil are long enough to feed through the top cover. The condenser is mounted up along side the new coil to get a good flow of cool air (previous advice from Eddie). Admittedly the original distributor and the ignition points are still in use so they need to be in good order and the points clean and correctly adjusted, but I have to say since making this change I have experienced no ignition problems and the bike always starts first or second kit.

Roy

 

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