Weird electrical Issue - Ducati.ms

velocidave · Jan 6th, 2012, 7:53 pm

OK, so its been cold here (for Texas, 40's ish) and my bikes been slow to turn over, but generally she starts after a few minutes, so today it fired on the first push, but when I got to work, I shut it off at the security gate so I could hear the gate guard, and it wouldn't restart. It just acted totally dead. I push it forward out of the way, switched the key off to speak with a friend (who suggested I should have bought a Yamaha) and then I switched the key back on and thumbed the starter in frustration, it fired right off. No slow spin, no indication of weak battery, just a strong spin with immediate start.

So I rode it to the parking lot, shut it off, and just out of curiosity, tried to start it again, no joy, just clicking and dim lights. An odd thing was, when the key was on, the lights came on, and there was a very faint humming coming from behind the dash, which I have never noticed before. Nothing up there but the headlight relays right?

I waited til the end of the day to mess with it again, same deal, no start, just weak clicking. I jumped it (I know, I know), and it fired right up, I figured, well I'll ride it home and figure it out there (12 miles) I made about 800 yds, then it just shut off totally. No lights, no engine, no nothing. It sputtered just a minor bit right before it shut off. I let it sit for a few minutes, turned the key back on, and the dash lights were so dim as to be almost invisible, and obviously it wouldn't turn over.

So I left it overnight (its a controlled access facility (military) and I'll go get it with the trailer tomorrow, in the interim, anyone got any ideas?

I'm thinking, bad ground, or bad V/R.

BTW its a 2000 996, with a full size Yuasa battery, all original wiring, and std compression. Its always been slow to turn over, even on a brand new battery, but its never done this before.

davy.j · Jan 6th, 2012, 9:44 pm

If your bike is headlights aways on with the ignition on then the humming would be the headlight relay oscillating due to low voltage.
Sounds like a bad battery, bad earth connection or R/R.

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velocidave · Jan 6th, 2012, 9:51 pm

Quote:

Originally Posted by davy-j

If your bike is headlights aways on with the ignition on then the humming would be the headlight relay oscillating due to low voltage.
Sounds like a bad battery, bad earth connection or R/R.

.

I don't THINK its the battery because its relatively new, stays on a Tender, and how strong it turned when it did start. Im leaning hard toward R/R or a bad ground wire/connection.

davy.j · Jan 6th, 2012, 10:05 pm

The other obvious one to check is the ignition relay (the yellow one) as it supplies power to all the other circuits.
Best thing I ever did was getting rid of all the mechanical relays except the headlight ones and fitting solid state types.

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mbevans · Jan 6th, 2012, 10:13 pm

Put a voltage load on the battery. I've had 8 month old topp of the line batteries take a sh*t, and had cheap ones last forever. I consider them (batteries) just a roll of the dice.....

Tornado · Jan 6th, 2012, 10:42 pm

I'm with Mark on this one...Have the battery load tested.

916duc · Jan 9th, 2012, 4:49 am

Seems like you're running off the battery until it's dead. Replace the VRR and charge the battery again.

Slower than you · Jan 9th, 2012, 10:06 am

Charge the battery and get it running. Put a voltmeter across the battery and you should have 14.5 volts over about 3000 rpm. If it's lower you have a charging problem.

Check the connector from the alternator. The one with the 3 yellow wires. These are known to burn up and leave you without power to the rectifier.

If yours is a single phase it'll have different wires of which I am unfamiliar.

phil996 · Jan 10th, 2012, 11:36 pm

definitely check your ground strap. Also I have replaced many sets of battery cables with upgraded ones we made from car audio stuff to get more cranking amps to the starter. Also check the starter solenoid, including the 2 prong wire that tells it to click. Good luck,

vtwin · Jan 11th, 2012, 4:02 am

When you switch the key on, your fuel pump primes normally? that's not the hum you were hearing?

ok, also check the starter solenoid/relay connection. It's the small round thing just beside the battery. the small connector at the back is known to come loose from time to time.
/edit: DAMN! I really should learn how to read! Phil above just said the same thing I did.. *doh*