Earth?

jakepeewee

Happy new year to you all!

May all your wishes come true and that you, your loved ones and your 851/888's will stay healthy.

My 851SP3 is still a work in progress.
I am currently wrapping my head around the spaghetti loom. I am not much into electrics and am trying to fit the loom again after spray painting the frame.

Not very clear to me what the main earth contact for the frame is.
Is somebody able to help me out?

Jacco

brad black

there's a welded on round boss on the frame on the lh side around the throttle body sort of area from memory. a few earths go there. scrape the paint off so you get good contact.

jakepeewee

Hi Brad,
I think I know what boss you mean, thanks.

Jacco

Mr.R

Brad is correct for bikes up to '91, after that from '92 onwards the only earth that I know of is the main earth at the rear of the righthand crankcase.

Steve R

jakepeewee

Well, mine is an SP3 so a 91.
And I do also have the earth at the rear of the right hand crank case, and I guess there's a lead straight from that earth boss to the battery minus?

griff851

That would be it, same as later models, monsters etc. just make sure it's a decent diameter wire. It has to take all of the current. Crimp and the solder and your in.

jakepeewee

Thanks Griff, will do.

I took a lot of pictures when uninstalling the loom but you always need the pictures that were not taken.
And the engine was already out of the frame years before I took out the loom.

When looking at the pictures I did make, there seems to be an earth lead from the boss on the left hand side of the frame to one of the mounting points of the air pressure unit (the blue one), but that makes no sense since this unit is mounted in these rubber fittings and thus isolated from the frame. I wondered if this lead is the one that should be between the earth point of the crank case and the battery, but the diameter of this lead seems to be too limited?

griff851

Is your regulator mounted at the front behind the steering head. Is it earthed?

jakepeewee

Yes, it is mounted behind the steering head. Bought a new mosfet regulator (carmo electronics) but I still need to connect it to the loom.

griff851

Regulator bodies need to be earthed, so perhaps that’s where it goes. As you mentioned there is no point in earthing the air pressure sensor. The ecu need to earthed as well.

brad black

most modern regs don't need the body earthed, but ime if you don't connect the original earth wire to a reg mounting bolt the owner will think you're an idiot, so you just do it and save the idiotic agro.

jakepeewee

brad black wrotemost modern regs don't need the body earthed, but ime if you don't connect the original earth wire to a reg mounting bolt the owner will think you're an idiot, so you just do it and save the idiotic agro.

Brad,
In this case the owner already knows I am an idiot, so carte blanche I guess.

brad black

always a bonus heading in.