Strange electrical problem

[Nik]

I've had an ongoing issue for the last few weeks with my Cosa. The chassis is permanently live - can see it arcing across between throttle wheel and chassis even when there is no feed to the lighting connected. Cosa's have metal throttle wheels BTW.


Fired the engine up with no connection to regulator or rest of loom - chassis not live. So it's not stator related.
Attached the live feed to the regulator, which wasn't fastened to the chassis. Chassis not live. So it's not the unregulated feed.
Attach the earth to the regulator. Still not live.
Fasten the regulator to the chassis with the same wires attached... chassis goes live, measuring 18v across the chassis to engine.


What the hell is going on here?

Anyone want to take a guess?

My only suggestion is that the wiring behind the airbox that runs to the regulator may be damaged, and earthing out when flexed to join the regulator. Problem there is, I can't get the bloody airbox off to get to it... anyone know how? It's a Mk1 Cosa 200 LX.

Cheers.

[coaster]

It sounds like your engine may not be earthed to the chassis and it is earthing via the throttle cable Try running a wire from a bolt on the engine to a bollt/screw on the chassis and see it that removes the arcing

[Nik]

Did that early on, sorry... same things.

The bit that gets me is the bit where it goes live when I bolt the regulator to the chassis. But if I measure across from regulator to earth before bolting it on, there is no current at all (presumably as it's earthing the correct way).


Sod it for now, I'm getting the P2 sorted first now.

[Speed Demon]

If you add about a litre of petrol to the headset and try the same test it will sort itself out.

[mark]

You like cosa,s yet you called me ugly?

[coaster]

Fasten the regulator to the chassis with the same wires attached... chassis goes live, measuring 18v across the chassis to engine.

You say you have tried earthing the engine but you CAN'T have. Try again but use a proper earth lead and make sure that you have a bare metal connection both ends. You can only be getting a reading on your meter if there is a potential difference (resistance) between the 2 points of contact :wtf:

[Nik]

Mark, you are ugly, but not as ugly as Speed Demon.

Gits, the pair of you...

I'd say a strap running from chassis to top bolt on the flywheel cowl was earthed...

[coaster]

I'd say a strap running from chassis to top bolt on the flywheel cowl was earthed...

I'm mearly stating the obvious, the earth you fitted couldn't have been a good one otherwise it would be impossible to get the reading you say you did. You were effectively putting your meter at opposite ends of a conductor, no way would you get a reading unless there was a bad connection:? Anyway, you know best

[goldeneye]

nik, why not just rubber mount the regulator, then earth it with the earth wire? i"m sure your not bothered about authenticity! my old Cosa had a hole drilled in the panel, a bootlace and duffel coat toggle combination as the choke pull on the P200 carb, as the Cosa carb had nackered. cost me £100 for the scoot, ran it for two years as a work bike, sold it for £200! Cosa"s are great, i"d have another tomorrow (for £100 like!)

[sean brady scooters]

silly question maybe but is the battery /leads the right way around