Where on the frame?

Hi guys,

I'm trying to find where the positive battery terminal earths to, can't find any pics. I'm sure I need to remove the paint on the new frame somewhere and nut and bolt the terminal. Question is where?

It's a '71 Commando.

Thanks.

Steve

Fastened to the rear of the right side Z plate I thought?

....but not under the zener as is often found?

Hegel said:

I'm trying to find where the positive battery terminal earths to, can't find any pics. I'm sure I need to remove the paint on the new frame somewhere and nut and bolt the terminal. Question is where?

Click to expand...

All standard electrical circuits on a (pre-MkIII) Commando ultimately return to the battery(+) through the red harness wiring.

There are a number of 'frame' connections to the 'return' wiring, however, there isn't any specific 'battery-positive-terminal-to-frame' mounting point-if that's what you're looking for?

Thanks for the replies guys!

Z plate, wow...I'd never would have thought it'd end up there! :shock:

I've been looking at the standard circuit diagram for the '71, the positive side of the battery just shows it terminating to earth, so yeah the red wire that you screw to the battery terminal...Oh I see what you're saying, but as you say the frame 'is' ultimately connected to the + terminal though?

Boy... that's going to cause some head scratching!

Thanks!

S

Red wire from my battery ends up at the mounting bracket for the coils, under where the condensers used to be. It also goes to the Z plate under the diode, but I'm not sure how it gets there. Also used to be a wire from the bottom most stud on the engine to the bolt that holds the bracket on for the prop stand, but I found I didn't need it any more.

You may find on your bike you need ground jumpers from and to certain points to get all the lights to work right. YMMV.

Dave
69 S

On my 850 1974 RED wire( 3) apparently came from battery to the HEAD suspension bolt
https://picasaweb.google.com/lh/photo/m ... directlink
I have find that long the route only one RED (the central) have the insulation badly damaged by heat due power overeating cargo
All the electrics operations components of the motorcycle are working in good manner .....and I am very uncertain to how find the reason of overheating
I can double or cut and substitute the RED cable damaged with one better dimensioned to avoid overheating,
but this not solve the question - Any trick to find the component that eating so much

searunner said:

On my 850 1974 RED wire( 3) apparently came from battery to the HEAD suspension bolt
https://picasaweb.google.com/lh/photo/m ... directlink

Click to expand...

I don't know if you are aware of it or not, but that is not the standard head steady in your photo?

searunner said:

I have find that long the route only one RED (the central) have the insulation badly damaged by heat due power overeating cargo
All the electrics operations components of the motorcycle are working in good manner .....and I am very uncertain to how find the reason of overheating
I can double or cut and substitute the RED cable damaged with one better dimensioned to avoid overheating,
but this not solve the question - Any trick to find the component that eating so much

Click to expand...

Trace the fault, if there is one, simply doubling-up the wiring is not the answer.

A common mistake often made by owners is to fit a fuse of the wrong Amp rating. The original Lucas '35A' fuse is the blow rating which is equivalent to a 17A continuous rated fuse. If the blow rated 35A fuse is replaced with a 35A (or similar) continuous rated fuse it will not blow until 70A which can burn out the wiring before the fuse blows-if it actually blows at all.

searunner said:

On my 850 1974 RED wire( 3) apparently came from battery to the HEAD suspension bolt
https://picasaweb.google.com/lh/photo/m ... directlink
I have find that long the route only one RED (the central) have the insulation badly damaged by heat due power overeating cargo
All the electrics operations components of the motorcycle are working in good manner .....and I am very uncertain to how find the reason of overheating
I can double or cut and substitute the RED cable damaged with one better dimensioned to avoid overheating,
but this not solve the question - Any trick to find the component that eating so much

Click to expand...

no its not the std head steady and if you don't replace it you will end up flogging the centre thread on your head.

Hegel said:

Hi guys,

I'm trying to find where the positive battery terminal earths to, can't find any pics. I'm sure I need to remove the paint on the new frame somewhere and nut and bolt the terminal. Question is where?

It's a '71 Commando.

Thanks.

Steve

Click to expand...

I hope you don't remove any paint. Its not necessary. I suggest you run earth wires to allyour major components on that bike that don't have their own earth wires. Especially the head lamps. They work best through relays as well.

spelky said:

Fastened to the rear of the right side Z plate I thought?

Click to expand...

Wondering myself. Is this what I found while tightning everything? I didnt want to start messing with it until I know what it was.
Is this the main positive earth connection?
I want to clean it up and reposition a couple of things. Do this with care?
Still learning.
Thanks

MikeM said:

Is this the main positive earth connection?

Click to expand...

No, not really, there are other 'earth'/'ground' connections. You could say the 'main' connection is the one that goes to the head steady.
Although there is likely to be continuity between the Z plate and the frame under most conditions, that particular connection provides a good return for Zener diode as it is fixed to the Z-plate, not the frame.
There is usually another earth/ground near the rectifier (either a ring terminal, or a spade terminal to the rectifier +stud) and another one inside the headlamp shell.

kerinorton said:

no its not the std head steady and if you don't replace it you will end up flogging the centre thread on your head.

Click to expand...

Yes it is NOT - I have find this head steady (PO?? and also badly damaged on the other side)
https://picasaweb.google.com/lh/photo/N ... directlink
I have decided to change it to a more effective (and 3 points) systems - Any suggestion for substitution? (in the restoration I am moderately prone to follow orthodox substitutions- but I know there are a lot of better alternatives for HEAD SUSPENSION, and this is a hidden particular)

FUSE I am friendly with English wiring harness problems, I haven't already controlled the fuse, but probably your supposition are correct
I should find a massive cooper barrel inside

I'm learning something new an interesting every day with this bike.

I'd made the assumption( I know what they say about assumption!), that it's be something similar to a lot of old Japanese bikes I used to work on. They used to have a fat old lead that'd bolt straight to the frame + others that'd scoot off around the rest of the bike. I'd like to try to connect everything up as it should do originally rather than make a guess as to where they'd 'earth' out. Any pics of looms and terminations would be greatly appreciated!

Thanks again!

Steve

Hegel said:

I'd made the assumption( I know what they say about assumption!), that it's be something similar to a lot of old Japanese bikes I used to work on. They used to have a fat old lead that'd bolt straight to the frame

Click to expand...

Many old Japanese bikes have electric starters, so "one fat old lead" is exactly what's needed, same for the 850 MkIII as electric start bikes shouldn't have any secondary light gauge return wires connected to the battery (although the 850 MkIII wiring diagram does show a second battery earth wire) as the heavy starter current can attempt to return to the battery through the harness wiring and which is not protected by the main fuse, if the heavy return cable connection should become loose or corroded.

searunner said:

I have decided to change it to a more effective (and 3 points) systems - Any suggestion for substitution?

Click to expand...

The Taylor head steady (with or without spring) would be one option.
http://www.rgmnorton.co.uk/buy/dave-tay ... s_2776.htm
http://www.rgmnorton.co.uk/buy/dave-tay ... s_2777.htm

The three head steady to cylinder head 067745 Allen bolts/screws are 5/16" BSF

http://www.rgmnorton.co.uk/buy/head-ste ... f_2780.htm

The MKII heavy ground bolts up to the engine case ( same gauge as starter/solenoid cable), behind the left side of the barrels. Looking at your pictures it appears all the loom grounds are the same. Zener, steady head, coil bracket and inside headlight shell (probably more) all have smaller gauge wires attached. I have yet to locate a heavy battery to frame ground wire.
Pete

Deets55 said:

The MKII heavy ground bolts up to the engine case ( same gauge as starter/solenoid cable), behind the left side of the barrels.

Click to expand...

MkIII ?

Deets55 said:

Looking at your pictures it appears all the loom grounds are the same. Zener, steady head, coil bracket and inside headlight shell (probably more) all have smaller gauge wires attached. I have yet to locate a heavy battery to frame ground wire.

Click to expand...

Hegel hasn't posted any pictures in this thread so far, and there wouldn't be any need to have a heavy gauge cable on a non-electric start Commando :?

L.A.B.

Stand corrected, I mean MKIII. The screen on my phone small and my eyes are old.
I mentioned this in reference your post about Japanese and/or MKIII wiring.
The pictures I am referring to were from previous posts from other members showing the head steady and Z bracket connections. My intent was not to correct you, but to supply addition information to the original question "Where on the frame?" based upon what I seen on my bike.

Pete

Hi all
after complete rewiring of two English Veteran cars - I am not alien from the English electric school,
but this is my first English motorcycle.
my Norton 850 II 1974 have one harness that appear original and unmolested to me, undamaged, trouble less and road worthy -
I have find the usual, short MAIN crop, of wire from the battery POSITIVE to the frame GROUND is not a new - the others GROUND connections, on the moto-frame- can be considered as "secondary" GROUND points.
The use of 3 wires- joined to the same connections - can be used to increase the power (Amperes) transferred, maintaining a good flexibility -
The very strange phenomenon are that the 3 wires (all same diameter,all joined from-to the same connections,all same length)
only ONE (the central)are damaged by heat, usually, in the same situations "short or over-absorption " all 3 wires are damaged in same manner.
I now will control the type of fuse used and if on the harness (and inside the headlamps)others wires are damaged by heat (exp. the RED ones)
then with a tester I will control the MAIN GROUND connection - with the semi burn wire on - and with wire cut-off-
then I replace the damaged wire with a enhanced one (at external route, from harness)