Earth Question... - V50

On the '79 V50 I am modding, the previous owner had all the earths going to one bolt that secures the battery tray with all different connectors. Ideally, dividing this up between two earth points would make sense as the tray might actually seat properly. Anyway…my question…The battery tray I am using is spray painted and the frame powder coated. I have filed back two corners of the battery tray around two bolt holes and will mount all the earths there. Is that all that is needed for a sufficient earthing point? I don’t need to take powder coat off the frame too do I? thanks

You have to do all which allows a low resistance path from the engine casing to the battery negative terminal.On my V50 the main earth is on the brake master cylinder bolt, and there is another on on the master cylinder under the tank, which earths the rectifier. If the powder coating on the frame does not allow a low resistance path between these points, very little will work.Those star washers are useful, they bite through the coating if you put them between the eyelet terminal and frame.

Guess I won’t know until I try whether the powdercoat will allow a low resistance path or not. Interesting thought about the star washers penetrating the powdercoat…I could put one under each bolt hole of the battery tray. Thanks Brian!

It is one problem with powder coat you DO have to remove it for any earth.

The big problem is if moisture gets under powdercoat it causes corrosion.

If you have to remove the powdercoat to get your earth I would suggest you file it away beyound the hole then seal the edges with paint.

Personally I would not go for a powdercoated frame, fine on show bikes but once there is any chip in it the damp gets in and under the coating causing corrosion. By the time it them bubbles up through the powdercoat it can be game over.

Thanks for the advice. I think with any future project rather than powdercoat I might see if anodising, or something similar, a frame might be a possibility.

To be fair the best way is good old paint, done properly it is alot easier to touch up when the inevitable stone chips hit it, anything else on a road bike causes problems. It was the thing to chrome or nickle coat a frame that caused all sorts of problems.

I think the powder coat frames look terrific but better on a show bike than one that is used in the UK , but hey it is just one opinion.

earthing on a powder coated frames etc is easy to do - first make sure the threaded hole in the frame is clean - run tap in it to clear out any powder coat coat internal thread with copper slip then you can get a good earth via the bolt would put a crinkle shake proof washer on bolt head then a new clean washer followed by the earth wires all with clean lugs on them then clamp them all up tight

I work with kit cars which, by and large, have GRP bodies.

To be sure of good earths I run heavy duty wires direct from the battery negative terminal to captive bolts strategically placed around the car then I take all my earth connections from these.

I did the same when I rebuilt my Cali III FF a few years back.

By doing this you are not relying on the frame/chassis to carry the earth supply and you do not need to worry about paint, rust or any other factor interfering with the earthing points.

It is certainly worth running a heavy earth cable from the battery to a suitable bolt on the engine/gearbox (starter motor bolt?). Halfords and similar places stock these cables in various lengths.

When I re wired my lemon, I made an earth cable, by buying the cable, the eyelets and using a blunt chisel to crimp the eyelets to the cable, I then soldered them, using a small blowtorch and electrical solder,

Fitted from the battery to the gearbox bolt!

I do like GTM, that is, I use a heavy grade thin wall cable that runs from front to back and splice in spurs to provide a sound earth usually via yokes, engine/gearbox, battery, frame and rear sub frame. This provides an effective central earth cable to which all other earths are connected.
This in effect replaces most standard earth wiring with a short run the the central cable.
Overkill perhaps but it works for me, I always think most Guzzi electrical faults originate with a poor earth.

You can’t have too many earths!

PS: the above is in addition to the usual battery strap
PPS: I use powder coat over paint wherever possible. It’s cheaper and more durable. The only time I have seen problems such as GB mentions is with MG original coatings

thanks guys…lots of brilliant advice. i know what i need to do now

When I rewired my Norton I took advice and used welding wire as the earth wire from the battery and used it for the wires to an from the starter motor I crimped eyelets on both ends. The advantage of using welding wire is that it is thick copper BUT is made up of hundreds of narrow strand wires and is therefore extremely pliable so can be curved round various bits and pieces of the bike to get to it’s destination.
I also made sure all the small items had earthing wires, lights, horn etc. and earthed them to the one place, that way all the earths are easy to check should anything decide not to work properly. For the earth connections I used a copper multi spade connector from Vehicle Wiring Products, they come with a varying number of connections and are fitted with bolt holes so they can be attached, I also got the welding wire from there. I think the main thing with electrical stuff is making sure you have a good wire to spade/bullet connection.

What a great website Vehicle Wiring Products is! Seen plenty of clips and things I need so will be getting some stuff from there…Cheers!

Most elektrikery problems can be traced to a bad or corroded crimp joint/earth or corroded fuse , now and again a pinched cable after you have put something back.