Earth to Earth, Ashes to the Aussies

chrisk

chrisk

Hero member
Location
Brisbane, Australia
Pardon the cricket pun in the subject  :P

Should I. put an earth lead to the starter, or just rely on the earth strap, from battery to frame.
What say you?

Earth to starter 'looks' messy.
 
Can you earth the battery to an engine mounting bolt? I should have thought that would be OK...
 
I ran an earth lead to the starter, but then I ran em all over the place as well to be sure to be sure
 
Years ago John Wilson fitted a welding cable to my starter and back to the battery. Its routed against and behind the frame and low on the engine case, in black is hard to see. Might be hard to hide on your application.
 
Thanks, but I exposed the bare metal on the frame, bolted an earth cable from the battery.
If it causes any problems, it's an easy fix. I can't recall any other Lavs I've had the had the eart to the motor, straight from the battery.
 
One earth to frame & another earth to engine. It doesn't have to go on the starter motor itself as long as it's on the crankcase somewhere, on an engine mount perhaps. I have mine on the breather housing of the RGS.
HTH

Smiddy
 
mauricejota7604 said:
120 Engines have an earth to engine as the engines are rubber mounted,
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Correct hence the second strap.

On a non rubber mounted engine you shouldn't need the second lead as long as there is a good point of contact between the frame and the engine so ideally you should scrape away the paint from one of the mounting points on the frame where the engine sits, use some anti corrosion such as  Corrisionx spray or dielectric grease and should be OK. A good star washer on the strap from the battery to the frame and a small amount of the above is also a good move.

You can easily do a voltage drop test from the engine block to the battery negative if you want to ensure that is sound if you wish.

 
You don't need an earth to the engine on a 120 even though it has a rubber mounted engine. The starter motor and other engine electrics will earth via the countershaft sprocket, 50 odd links in the chain, rear wheel sprocket carrier and ball bearings, and via swing arm bushes back to the frame. What could be simpler? If that's not enough, it'll also earth via the clutch cable. How many earths do you need?
 
Most of my bikes have an earth strap from engine to battery regardless of whether it has rubber mounts or not. Peace of mind.
My RGS came to me with a clutch cable fitted but it's far from standard..
 
Grant said:
Never seen a standard 120 Laverda with a clutch cable.
Click to expand...

Therefore a standard 120 wouldn't be prone to doing clutch cables  ::)
At work we have hot wires that always break at the exposed areas, whereas areas that are covered, like a cable outer, isn't where they break.
 
Dellortoman said:
You don't need an earth to the engine on a 120 even though it has a rubber mounted engine. The starter motor and other engine electrics will earth via the countershaft sprocket, 50 odd links in the chain, rear wheel sprocket carrier and ball bearings, and via swing arm bushes back to the frame. What could be simpler? If that's not enough, it'll also earth via the clutch cable. How many earths do you need?
Click to expand...
Ever seen a fried accelerator cable ? also the rear sprocket is mounted via a cush drive, the chain will be O ring so whilst in theory you could get away with it ........you are asking for voltage drops so much easier and safer just to an earth cable.
In fact back in the day we always used to run the earth strap from the starter mount bolt and still do as it goes to minimise any chance of voltage drop.
You need to minimise any voltage drops in the starter circuit to avoid over working the damn after thought being the dreaded starter clutch.
 
Dellortoman said:
You don't need an earth to the engine on a 120 even though it has a rubber mounted engine. The starter motor and other engine electrics will earth via the countershaft sprocket, 50 odd links in the chain, rear wheel sprocket carrier and ball bearings, and via swing arm bushes back to the frame. What could be simpler? If that's not enough, it'll also earth via the clutch cable. How many earths do you need?
Click to expand...

Sending starter motor currents up to a couple of hundred Amps through ball bearings will destroy them in no time. Not recommended.

In case of electrics, especially on bikes, I prefer better safe than sorry. Even with the rigid mounted engine on my 3C I decided to add an earth cable (10sqmm) between the battery earth and the engine, just where it is needed most.
Starter_ground.jpg


Loads of grunt on the starter motor, BTW. IMHO the additional cable blends nicely in, did my very best to give the rivet counters a run for ther money. :D
Engine.jpg


In addition, I have an earth strap running from battery earth to one of the tool tray bolts, meeting up there with all other earth cables (ignition, R/R, rear light, relais, ground wire to headlight shell etc.). All earth currents running in copper. Only electrical function of the frame is to form a faraday cage, protecting electronic components from lightning stikes.  ::)
Ground_wiring.jpg


Regards,
Stefan
 
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