Grounding to Z-Plate

Hello everyone,

In a puff of smoke last week, I fried a portion of my wiring harness. Not sure why it shorted out, but I was able to repair the damage (fortunately, it was only one red ground wire from the battery to the rear foot peg). Can someone verify that I've got this thing hooked into the right place? According to the Clymer manual, the ground should be attached to the back side of the footrest bolt. Seems strange to me since I didn't think aluminum was a good grounding point. Picture 1 below.

Also - a ground wire broke off near the front of the bike that was grounded to the engine/frame (head steady?). Since the wire is short now, can I attach to the plate that is directly behind it (similar to the other red wire in photo 2)?

Thanks!

Kevin

FreeRad,
Did you find why there was a dead short? You need to investigate why your ground wires fried. :shock: Double check by removing your tank and inspect the multi wired rubber grommet that very often disintegrates to expose wires to ground where it should be insulated. How old is your wire loom?
Regards,
Thomas
CNN

FreeRadical said:

Can someone verify that I've got this thing hooked into the right place?

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Yes.

FreeRadical said:

According to the Clymer manual, the ground should be attached to the back side of the footrest bolt. Seems strange to me since I didn't think aluminum was a good grounding point.

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The red is only intended as a "ground" (return) for the Zener, and not a ground for the battery.

FreeRadical said:

Also - a ground wire broke off near the front of the bike that was grounded to the engine/frame (head steady?). Since the wire is short now, can I attach to the plate that is directly behind it (similar to the other red wire in photo 2)?

Click to expand...

Yes.

+1 w/ Lab on Z plate ground
Engine ground looks like it broke due to too short a wire and engine movement.
Puff of smoke? Maybe red wire hit against diode feed on Z plate?
Pete

How old is your wire loom?

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It is the original wire loom. I was repairing it just to get the bike up and running first, but plan on replacing it when I tear down the bike to paint the frame.

Can someone recommend a vendor other than Andover Norton who makes a good harness? British Wiring and TMS are two I've found on the forum.

Thanks!

Kevin

FreeRadical said:

Kevin

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Hi Kevin

If the rocker oil feed pipe in the photo is rubber hose you should replace it with the correct pipe as the oil pressure here gets pretty high. Rubber hose isn't going to handle it.

Double check by removing your tank and inspect the multi wired rubber grommet that very often disintegrates to expose wires to ground where it should be insulated

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It, too is quite crumbly!



When I order a new wiring harness, as it appears it will be sooner than later, is this part of the headlight loom or the main wiring harness?

Kevin

FreeRadical said:

When I order a new wiring harness, as it appears it will be sooner than later, is this part of the headlight loom or the main wiring harness?

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You probably need to order it as a separate item (10-way connector): http://www.britishwiring.com/C-336-p/c336.htm

Or, you could just use five "doubles"? : http://www.britishwiring.com/Double-Sna ... p/c312.htm

FreeRadical said:

How old is your wire loom?

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Click to expand...

It is the original wire loom. I was repairing it just to get the bike up and running first, but plan on replacing it when I tear down the bike to paint the frame.

Can someone recommend a vendor other than Andover Norton who makes a good harness? British Wiring and TMS are two I've found on the forum.

Thanks!

Kevin[/quote

I've been told the wire loom Commando Specialties sells leaves out all the extra wires not needed since the original looms were designed to include all the wires required for the police bikes. Before buying I suggest calling to confirm this.

illf8ed said:

If the rocker oil feed pipe in the photo is rubber hose you should replace it with the correct pipe as the oil pressure here gets pretty high. Rubber hose isn't going to handle it.

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Yes, those rubber hoses are a disaster waiting to happen.

With clamps on those hoses, they may last a few miles.
With no clamps, you'll be lucky to get that far before being showered in oil. !!

FreeRadical said:

In a puff of smoke last week, I fried a portion of my wiring harness. Not sure why it shorted out,

Click to expand...

You do know that these bikes, stock, are wired positive earth ?
Connecting the battery the wrong way can fry wires, and more.....

In a puff of smoke last week, I fried a portion of my wiring harness. Not sure why it shorted out,

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Actually, it was much more dramatic than that. I thought I was going to have to pull out the fire extinguisher when it happened. I believe the coil to the rear capacitor started to glow momentarily. At any rate, I repaired the damage to the ground wire and have it grounded to the z-plate. Now that I've got to replace the 10 bullet rubber connector, it makes me wonder how much more I should invest in this old harness!

If the rocker oil feed pipe in the photo is rubber hose you should replace it with the correct pipe as the oil pressure here gets pretty high. Rubber hose isn't going to handle it.

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Yes, they are just rubber hoses. Any reason not to go with the non-Andover braided cloth hoses that Old Britts sells?

Gates Oil Line, 3/8 ID, 300 PSI (part # 54-800005, $4.66 per foot). This hose has a woven cloth exterior similar looking to the original oil hoses and the following hoses are made from this hose:
Oil Line, Feed/Return, 17", 3/8 ID (part # 06-2200/G, $7.50)
Oil Line, Return, 12", 3/8 ID (part # 06-3144/G, $5.00)
Oil Line, Feed, 15", 3/8 ID (part # 06-2201/G, $6.70)
These hoses do not come with any hose clamps, they must be ordered separately.

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Suggest you make your own harness, and convert to a single point ground. Will eliminate many headaches, and you can quickly trace faults.

Thanks, L.A.B. for the cheap solution on how to fix the wiring harness. I ended up buying 5 of the double bullet connectors to replace the 10-way bullet connector. Thought I was home free so I hooked up the battery, turned on the ignition switch...and nothing. Main fuse was blown. PO had a 30A SFE fuse in it. Is this the correct size for the main fuse? Seems there is some debate about this, so I'll throw it over the wall.

Thanks!

Kevin

FreeRadical said:

Thanks, L.A.B. for the cheap solution on how to fix the wiring harness. I ended up buying 5 of the double bullet connectors to replace the 10-way bullet connector. Thought I was home free so I hooked up the battery, turned on the ignition switch...and nothing. Main fuse was blown. PO had a 30A SFE fuse in it. Is this the correct size for the main fuse? Seems there is some debate about this, so I'll throw it over the wall.

Thanks!

Kevin

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Kevin,
You must use the correct rated fuse or the same thing will happen. If you choose not to use the fuses from the British suppliers then get an automotive 17amp rated fuse. Do a search on this. Here is a teaser.
wiring-harness-smokem-t6254.html
Cheers,
Thomas
CNN

FreeRadical said:

PO had a 30A SFE fuse in it. Is this the correct size for the main fuse? Seems there is some debate about this, so I'll throw it over the wall.

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The original Lucas fuses were numbered using the blow amp rating, however, automotive fuses are usually numbered by continuous rating which is half the blow rating-so the old British "35A" glass fuses as specified in manuals and handbooks have a continuous rating of 17A.
If any other automotive fuse is substituted for the Lucas type then it needs to be the nearest continuous equivalent, usually either 15A or 20A (15A is usually enough).

A 30A continuous fuse won't blow until 60A, which could result in the wiring burning before the fuse blows.

http://www.groups.tr-register.co.uk/nen ... 20BUSS.pdf

Kevin
I didn't write this but it makes logic to me. Tongue firmly planted in cheek. :mrgreen:


ELECTRICAL THEORY BY JOSEPH LUCAS
Positive ground depends on proper circuit functioning, which is the transmission of negative ions by retention of the visible spectral manifestation known as ?smoke?.
Smoke is the thing that makes electrical circuits work. We know this to be true because every time one lets the smoke out of an electrical circuit, it stops working. This can be verified repeatedly through empirical testing.

For example, if one places a copper bar across the terminals of a battery, prodigious quantities of smoke are liberated and the battery shortly ceases to function. In addition, if one observes smoke escaping from an electrical component such as a Lucas voltage regulator, it will also be observed that the component no longer functions. The logic is elementary and inescapable!

The function of the wiring harness is to conduct the smoke from one device to another. When the wiring springs a leak and lets all the smoke out of the system, nothing works afterward.

Starter motors were considered unsuitable for British motorcycles for some time largely because they consumed large quantities of smoke, requiring very unsightly large wires.
It has been reported that Lucas electrical components are possibly more prone to electrical leakage than their Bosch, Japanese or American counterparts. Experts point out that this is because Lucas is British, and all things British leak. British engines leak oil, British shock absorbers, hydraulic forks and disk brake systems leak fluid, British tires leak air and British Intelligence leaks national defense secrets.

Therefore, it follows that British electrical systems must leak smoke. Once again, the logic is clear and inescapable.

In conclusion, the basic concept of transmission of electrical energy in the form of smoke provides a logical explanation of the mysteries of electrical components especially British units manufactured by Joseph Lucas, Ltd.

And remember: ?A gentleman does not motor about after dark.?

Joseph Lucas ?The Prince of Darkness?
1842-1903
Cheers,
Thomas
CNN

LOL - I've had my fair share of smoke! I will put the appropriate 20A fuse in the holder. Thanks!

Kevin

Back to troubleshooting a short. Put the 20A fuse in and burn it out immediately. Is there a way to isolate systematically? Could a bad capacitor cause this to happen? I'm afraid my electrical skills could use a lot of improvement. Thanks for your patience. :roll:

Kevin

FreeRadical said:

Back to troubleshooting a short. Put the 20A fuse in and burn it out immediately. Is there a way to isolate systematically?
Kevin

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I assume that you hooked your battery up correctly for positive earth (i.e. red wires to the positive terminal of the battery) and also I am assuming that your ignition switch was off when your fuse blew. If that is the case:

Your brown and blue wire (NU) from the fuse which is always hot once the battery is hooked up goes to the following:
1. Zener diode
2. Rectifier
3. 2MC Capacitor
4. Accessory Receptacle
5. Bullet connector that is not used (this was for police bike applications and should be paired with a purple and green wire)
6. Ignition Switch

I would use a multimeter (get one if you don't have one) and set the meter for testing continuity (the battery should be disconnected when doing these tests). There should be an audio setting on the meter or use the lowest ohm setting scale. Instead of a meter you could hook a 12 volt light bulb to the motorcycle's battery where the fuse would have gone for testing. If the light is illuminated, you have a short.

I would first connect one meter probe to the red battery terminal (ground) and the other to the negative battery terminal. Use a good fuse for this test or hook the meter probe to the place where the fuse would go. If you have a dead short your meter should be making an audible sound or read zero ohms. Simply disconnect the Zener diode and if the meter is still making noise (or zero ohms), go to the Rectifier and disconnect the brown/blue wire there. If the meter still is making a sound disconnect the brown/blue wire at the 2MC Capacitor. If this is still making noise do a visual inspection around the Accessory Receptacle to see if the brown/blue wire is being pinched or frayed. Make sure the wire is not shorting to ground. Then check the unused brown/blue wire that is paired with the purple and green wire. It should just be hanging down between the oil tank and the air filter assembly. Make sure that it is not shorted there via a visual inspection. If the meter is still sounding off, get to the wires at the back of the ignition switch. It is possible that the brown/blue wire could be shorted to the switch case itself. I save the ignition switch for last because those wires are somewhat difficult to get to.

After all of that if it is still making noise and you visually all of the brown/blue wire that is visible it's possible that the brown/blue wire was shorted with the red wire within the harness. Seeing as you have been smoking wires, that may be a possibility.

Anyway, that is how I would systematically go about finding the short. I hope this is of some help. Look at your wiring diagram and follow the brown/blue wire to each component, this will help you get a feel for what is going on.