conversion to negatigve earth.

Does anyone know where I can get the parts I will need to convert my 84 Commando to negative earth.

What is a 1984 Commando ?

And perhaps a few words on why you would want a negative/negatigve earth system....

I want to fit a new led headlamp to the bike which I am told require negative earth. I do realise I can rewire the relays so that are switched on the positive side rather than the negaqtive side. Just thought it might be easier. Might be a lot cheaper to just redirect the wiring to my 2 relays. The head lamp appears to be fully insulated so should work.

If the LED lamp don't ground/earth thought its mount then just switcheroo the relay terminals. If doing whole system then easiest is get modern reg/rec [wired for - ground and toss out the Lucas items it replaces or bypasses and remember to hook battery up right.

There are only 4 electrical items on a 1974 Commando that are polarity sensitive:

• 
  1. Zener Diode (voltage regulator)
  2. Rectifier (the alternators AC to DC converter)
  3. 2MC Capacitor (used for running without a battery)
  4. Spark Coils

To convert to a negative ground is pretty straightforward:

• 
  1. You will need to replace the Zener Diode to one with a negative ground.
  2. You need to replace the rectifier with an aftermarket bridge rectifier which you would need to wire negative ground
  3. Swap the wires on the 2MC capacitor. They have different sized terminals so those would have to be changed.
  4. Swap the primary wires on the spark coil

If you happen to have an electronic ignition, rewire that in accordance with the manufacturers instructions. You could also install an aftermarket voltage regulator which would replace both the Zener diode and the rectifier and then wire this to negative ground. I would also recommend labeling your battery wires because it may help as a reminder when installing the battery. One other thing, if you ever use that accessory plug on the right-hand side of the motorcycle, you need to be aware of which terminal is positive and which one is negative.

Lastly, there may be other items that have since been installed on your bike that may be polarity sensitive such as an electronic turn signal flasher, electronic warning light assimilator, and possibly relays that have a diode shunted across the coil.

+1 on going to a solid state regulator/rectifier. Also be aware of the fact that all you ground wires are now the Red wires some of them go directly to engine and frame grounding bolts. Very easy to think red wire is hot and black is ground.

The whole world is pretty much negative ground for DC electric products. Just bite the bullet and convert to a negative ground system and you'll never have to worry about any aftermarket devices being hooked up properly. Besides the increasingly popular LEDS, GPS, cell phones, radios, etc. are all negative ground systems.

I put LED indicators on my 72, just ran the wiring separate. Converting to neg earth is on my ' one day' list though.
In the mean time I binned the original charging system and fitted a 3 phase alternator and electronic voltage regulator. I'm not a fan of vintage charging systems.
If your headlight is insulated relays would be an easier first step.
Got any pics of the unit or a link as interested?

Good list of polarity sensitive components I've saved, thanx. Another thing that reversing polarity will drive nutx is the asssimulator amber lamp activator. I like to substitute with a color change LED vom in the shell hole.

Thanks for your information guys. First I will fiddle with the wiring at the relays as there appears to be no quick way to obtain the necessary parts to convert properly. I am happy with the original charging system so it will be ok to leave it. I just want to try this G E Nighthawk L E D lamp this weekend [ after the storm passes, yep only 130 km winds but too much to ride in. I was at college when the Wahine storm hit in April 10th 1968. 140 knot winds in that one. I was very lucky as I took shelter in one of the shop doorways in Onepu Rd while a huge gust went by. I took off across the road then another huge gust took out that same shop window. Man that was wind.] .

BTW, the lamp has a matt black painted alloy body so I wrapped insulation tape twice round it last night to see if it would still fit in the headlamp surround. It does. the lamp Is quite heavy compared to the standard h4 so I guess Steve, if you want to fit one, you are going to have to drill a few more holes somewhere. [ or diet, but your wife might think your lean enough now. ]

If I am happy with the performance I think I will have to convert as I reckon the insulation tape will eventually wear through because of the flogging round the engine creates.

So, can anyone point me in the right direction to purchase the necessary parts required as listed above. My computer scanning skills have a lot to answer for.

I also really want to put a photograph of some of the things I have done so the first step was to join PHotobucket. hmmmmmmmmmmm./ WTF next???????? Rome wasn't built in a day. [ I've got no patience either. Its got to be done or fixed now ]

All the best everyone and thanks once again. Dereck

Hey Dereck I delayed joining this forum almost a decade d/t the password crapola and know a few others that similar happened too and too much digital doo doo to get through so far. Photobucket is the standard photo place but changes its format now and then after ya get used to its quirks to learn to work around again.
Tag up a photobucket direct link next to displayed photo then copy it into the image icon in the icons about text here. Only really need the Tympanion or the nicer looking Podtronics single phase and just dissconnect or reconnect from above list.

https://www.google.com/#q=podtronics+regulator

BTW Commando life is simple for me as made decision to only use part numbered item on Trixie Combat and Peel get new electronic brain box wiring kit such as sold to custom everything Harley builders.

Dereck,

I replaced my H-4 bulb with a 65/100 watt bulb. With my bike off and headlight on it is brighter than my son running SV650 on both low and high beams. I have a Lucus 3 phase, Podtronis reg/rectifer and headlight relays. I also made up a better bulb harness by removing the light gauge wires and running 14 gauge marine wires for the whole system.

Pete

I use Photobucket.
I'll assume you have the pics on your PC.
Open Photobucket
Upload from you PC.
Once you have the photo on Photobucket
Open the 'links' option ( chain links icon)
select and copy the one called IMG
Go to your forum post
click IMG
Paste your picture.
preview to make sure its the right one.
submit.
Try that and see how you get on. :mrgreen:
If you get stuck PM me.

High. Many thanks you all there. Ill get the PB think sorted even if you have to grab me by the scruff of the neck and bang my head against a Harley.

deets. 100 watts means 8 amps draw. I like the sound of the 3.6 draw from the Nighthawk, and as Steve mentioned, I can always put a spot light beside it. I will see what happens with this new light when the weather gets better. We have too many closed roads here at the moment.

kerinorton said:

Does anyone know where I can get the parts I will need to convert my 84 Commando to negative earth.

Click to expand...

You do know that you risk being banned from all beer fridges and whisky cabinets in Ham. East if you show up having negatively altered your precious Norton. :mrgreen:

Includes ' The Tron"
Is East Tron sort of up market :roll:

72Combat said:

Includes ' The Tron"
Is East Tron sort of up market :roll:

Click to expand...

That depends on how low the starting point is.....

ntst8 said:

kerinorton said:

Does anyone know where I can get the parts I will need to convert my 84 Commando to negative earth.

Click to expand...

You do know that you risk being banned from all beer fridges and whisky cabinets in Ham. East if you show up having negatively altered your precious Norton. :mrgreen:

Click to expand...

Don't be afraid, my near mint 750 doesn't want to grow up.

ntst8 said:

kerinorton said:

Does anyone know where I can get the parts I will need to convert my 84 Commando to negative earth.

Click to expand...

You do know that you risk being banned from all beer fridges and whisky cabinets in Ham. East if you show up having negatively altered your precious Norton. :mrgreen:

Click to expand...

Don't be afraid, my near mint 750 doesn't want to grow up. The 850 doesn't care. Its already embarrassed me by falling over in my daughters driveway when it stalled on me. Did the front guard in doing that. Another time the bitch locked her front wheel up on me. Did the headlamp, indicators, handlebars, muffler, indicator switch, leather jacket, visor, both gloves, one hand grip. The bitch. Had me burning up a few kilojoules hiding the faults before the leanometer noticed it.

Dereck,
100 watts means 8 amps draw. I like the sound of the 3.6 draw from the Nighthawk

Excellent point, gotta love that LED technology. Now if we can just get the bulb builders to convert to positive ground HUMM.......

Pete