yellow a/c voltage wires heads up

[doslemans]

2004 V11 Lemans 76K miles. Was headed to the Kentucky Guzzi rally last Thursday In Frankfort and voltmeter I added a couple years ago indicated the charging system was fading away.  Was hoping to get to a town before it died altogether as I was out in the middle of nowhere.  Voltmeter flashes when it drops to 11.8 volts and I was surprised how soon the bike quit after that.  Luckily the cell phone got a signal and was able to contact guys at rally so they came the 80 miles to get me with a trailer.  After removing fairing and troubleshooting in the campground, the connector that the 2 yellow wires are in had overheated and fused together. Took 2 pair of pliers to persuade it to separate.  Cleaned best we could and removed burned plastic, tightened the terminals, and applied caig deoxit electrical magic.  Made it the 300 miles home Sunday charging better than it has since I added the voltmeter.  Need to  cut out the connector and replace with individual disconnects for permanent fix.  Any recommendations as to what type of disconnect terminals I should use?

[JBBenson]

The yellow wires form the RR? I put in a new one before mine quit. But the connectors were grungy.
 

Question is why yours overheated and fused. Possibly bad ground(s), weak or dying battery (I have found that batteries have been of poorer quality in the last 10 years) or failing RR.
 

If you discover the source, might be a good note for one of the checklists.....

[Lucky Phil]

3 hours ago, doslemans said:

2004 V11 Lemans 76K miles. Was headed to the Kentucky Guzzi rally last Thursday In Frankfort and voltmeter I added a couple years ago indicated the charging system was fading away.  Was hoping to get to a town before it died altogether as I was out in the middle of nowhere.  Voltmeter flashes when it drops to 11.8 volts and I was surprised how soon the bike quit after that.  Luckily the cell phone got a signal and was able to contact guys at rally so they came the 80 miles to get me with a trailer.  After removing fairing and troubleshooting in the campground, the connector that the 2 yellow wires are in had overheated and fused together. Took 2 pair of pliers to persuade it to separate.  Cleaned best we could and removed burned plastic, tightened the terminals, and applied caig deoxit electrical magic.  Made it the 300 miles home Sunday charging better than it has since I added the voltmeter.  Need to  cut out the connector and replace with individual disconnects for permanent fix.  Any recommendations as to what type of disconnect terminals I should use?

A fix as old as time. Those connectors have always been an issue.

Ciao

[nobleswood]

Which connectors are these ? I can't visulise where they are.

As the owner of a 2004 with 18500miles I should have a look.

[Lucky Phil]

1 hour ago, nobleswood said:

Which connectors are these ? I can't visulise where they are.

As the owner of a 2004 with 18500miles I should have a look.

Most likely cable tied to the front engine subframe. Two bullet connectors on yellow wires from the alternator.

Ciao

[Chuck]

3 minutes ago, Lucky Phil said:

Most likely cable tied to the front engine subframe. Two bullet connectors on yellow wires from the alternator.

Ciao

No, this was a Molex connector.. or used to be.

[Lucky Phil]

59 minutes ago, Chuck said:

No, this was a Molex connector.. or used to be.

Oh ok my mistake. 

Ciao

[doslemans]

Sorry to take so long to reply.  I have the extra ground that goes directly to the battery attached to the regulator.  I had the tank off last winter to do the checklist per this site to change air and fuel filter.  Also disconnected every connector including the yellow wires and the other 4 pin connector from the regulator to deoxit, too.  Perhaps I loosened up the spade terminals on the yellow wires when I did that and caused the bad connection and overheating.  Chuck nailed the location as he and his son were leading this repair effort.  Both connectors associated with the regulator are Molex type, tywrapped to the left front downtube just above where the left exhaust header exits the head.  You can see them if you look there but very limited access with fairing installed.  I was able to check them last winter with the tank off and fairing installed, though.

[MartyNZ]

16 hours ago, doslemans said:

...wires overheated and fused together. Need to  cut out the connector and replace with individual disconnects for permanent fix.  Any recommendations as to what type of disconnect terminals I should use?

My bike had bullet connectors on those two yellow wires, and after they melted and fused, I cut them off, slid on some heat shrink sleeve, fitted crimp connectors, applied DC4 dielectric grease (any grease is better than nothing) , and shrunk the heat shrink sleeve so the grease squeezed out each end. The joints have been trouble free ever since. The wiring is in a hostile environment with tire spray, and heat/cool cycles.

 

You will need to cut the crimps if you want to remove the engine or alternator stator in the future,  but the yellow wires were much too long so that would be no problem.

The reason the connectors melted was because of resistance in the connector caused by corrosion in the joint. Water, salt, oxygen, make the connection corrode, so the resistance goes up. Joules law says heat in a connection equals current squared times resistance. Say 10 amps through 2 ohms gives 200 watts of heat. 10x10x2=200W.  That's more than enough to melt the connectors. We often see the same in the 30 amp fuse melting. Clean and sealed connectors can last, if water and oxygen are excluded.    

[Chuck]

Kiwi Roy sez use Vaseline.

[nobleswood]

Glad I asked as I'm pulling the alternator to replace the timing chain tensioner & leaking gasket. So I'm in the general vacinity.

[Kiwi_Roy]

Why do you need to disconnect the wires?

Chop the connector out and use a couple of crimp links or solder the wires. If you ever need to replace the wires make them a bit longer so if you ever need to chop them you have enough length to shorten them.

Heat is resistance x current squared and I believe the current spikes are very high leading to lots of heat.

Also i think the crimp connectors available in The America are smaller than the OEM Guzzi ones.

[doslemans]

Good point Kiwi_Roy.  Only time I have ever disconnected them is once during tank off maintenance checklist and second time to fix overheated/not charging situation last weekend.  Will do your suggested fix when I get back home from Barber Vintage Motorcycle Festival next week.