Charging system??

[Dan Beaman]

This topic, I'm sure has been covered numerous times, but my search wasn't turning up what I thought I was dealing with.

I have an '81 G5 with about 94,000 miles on it going strong!  LOVE this bike.

The issues:

*My headlight is extremely dim on either high or low setting. It's dim enough that I will no longer ride it at night. Bulb is new.

*My horns don't work.  At night, I can see the lights dim when I hit the button. When the machine is sitting without the engine running, I can hear the relay kick in and the horns getting power.

*My fuel economy has dropped from lower 40's to mid 30's.

*Brake and turn signals all seem strong. 

*The bike just won't idle!  The idle set screws seem to do nothing now.

Is this all symptoms of one issue. I'm feeling that if I have a regulator/rectifier/ground problem, it may be affecting all these systems for different reasons. Am I off base? The fuel issues could just be age on the carbs. It runs like a banshee and cruises wonderfully.

Don't get too technical on me folks. Electrical genius I'm not!  Your input, though, is REALLY appreciated.

[dilligaf]

This problem has been cover many-many times here on Wild Guzzi.  Put the battery on a charger and charge the battery.  Attach a DC voltage meter across the + and - post of your battery.  This reading should be north of 12VDC.  Start the motorcycle and rev to 3000 RPM or so.  The voltage reading should increase to 13.8 VDC.  IF THE VOLTAGE does not increase you have a charging system problem.  :BEER:
Matt

[Dan Beaman]

 ;-T  That much I knew Matt! But hey!  Thanks for the input!  ;D  Now WHAT charging system problem???   ???

[twhitaker]

My Convert had brushes on the alternator. Think after 34 years they might be worn down?

[travelingbyguzzi]

2 quick easy and free things you should do on older Guzzis every couple years:

Check the four screws holding your diode board (rectifier) on. They must be Tight. this grounds the system. Many people run a ground wire from one of these screws to the battery ground post.

Also, spin your fuses in their seats. I just spent a couple weeks chasing a problem on my Cal II. that was it. A slightly corroded fuse.

[dilligaf]

My Convert had brushes on the alternator. Think after 34 years they might be worn down?

Ya think.  ;D

;-T  That much I knew Matt! But hey!  Thanks for the input!  ;D  Now WHAT charging system problem???   ???

And that is what the search function is for.   ::( As I posted WHAT charging system problem has been covered many-many times.  :BEER:
Matt

[Dan Beaman]

Well gee Matt, so sorry you had to get your panties in a wad. I did a search and didn't find what I was looking for.

Terry, the brushes have been replaced within the last 3 years as has the rotor.

TravelingbyGuzzi... . Thanks for your input. This is helpful and gives me a better starting point.

Apparently the overall helpful nature of this board has changed from what it used to be so I'll start looking elsewhere.

[Kiwi_Roy]

There are a number of things that could be contributing to poor charging, the bike is 34 years old
Check the alternator brushes, they should be about 3/4" long
Check the resistance between each yellow wire at the rectifier
Make sure all the connectors in the alternator are clean and tight.

As Bill says the grounds around the rectifier and regulator

Disconnect the battery and go over all the connectors, I dip them in petroleum jelly aka Vaseline to protect against corrosion
As for the headlight
Clean the ignition switch, all the power goes through there
Clean the fuses as Bill mentions, bend the clips to get a good tight connection
Make sure all the connectors on the fuse block are tight
The connectors burn out
Poor grounding of the headlight

The biggest improvement I made to the lights on my Cali II was add a pair of headlight relays inside the bucket this takes all the current away from the tired old dimmer switch and it's tiny connecting wires. I powered the relays from the red wire going to the ignition switch. Easily 20% brighter than before.

For safety I added a new 40 Amp in-line fuse to the battery end of the red wire

Update:
As for the idling problem
Eliminate bad electrical supply by monitoring the 12 Volt common connection at the coils with a small lamp, there should be no flickering
Measure the Voltage with a meter if you have one.
Do you still have the side-stand switch?

[davedel44]

Calm down Boys!  Take some deep breaths and play nice.
Dave
Galveston

[Dan Beaman]

Thanks that helps too. The battery connections are very good. It was just replaced this spring and all the contacts were cleaned up and coated. I pulled the fairing off last summer and untaped all the wiring, cleaned it all and made sure all of those connections were clean (shiny) and reconnected everything under there. I have suspected the switches a few times, but I think the diodes are a better starting point with how some of you have explained it.

Thanks guys.

[LaMojo]

If the battery starts the bike then it's not the charging system. Check all of the grounds especially inside the headlight bucket.  With the headlight on, the ground connection(s) should be warm to hot to the touch especially on the headlight circuit.

[jacksonracingcomau]

If the battery starts the bike then it's not the charging system. Check all of the grounds especially inside the headlight bucket.  With the headlight on, the ground connection(s) should be warm to hot to the touch.

 :+1

And if they are hot, dismantle, clean and tighten
Actually do this anyway, the root of all evil is a bad earth, many bad earths is truly wicked.
Nothing wrong with system, just bad connections.

But I think mpg and idling problems are something else, give it new plugs and a tune up, timing and carb clean, sync etc,  report back

[dilligaf]

If the battery starts the bike then it's not the charging system. Check all of the grounds especially inside the headlight bucket.  With the headlight on, the ground connection(s) should be warm to hot to the touch especially on the headlight circuit.

I agree however, the best way to be sure is:  Attach a DC voltage meter across the + and - post of your battery.  This reading should be north of 12VDC.  Start the motorcycle and rev to 3000 RPM or so.  The voltage reading should increase to 13.8 VDC.  IF THE VOLTAGE does not increase you have a charging system problem.   :BEER:
Matt

[jacksonracingcomau]

I agree however, the best way to be sure is:  Attach a DC voltage meter across the + and - post of your battery.  This reading should be north of 12VDC.  Start the motorcycle and rev to 3000 RPM or so.  The voltage reading should increase to 13.8 VDC.  IF THE VOLTAGE does not increase you have a charging system problem.   :BEER:
Matt

 OP has not mentioned a flat or boiled battery, the only reasons to check charging
symptoms as written are bad lights and horn but not flat battery or charge light staying on, let's try and find cause of problem he has.

[Dan Beaman]

The issue with the horns happens even with the ignition switch just turned on and the engine off. The engine starts fine every time so I know it's charging. I suppose that's still pointing to grounds. If the grounding was poor, that would also give me weak lights too.  A guy I work with suggested that the poorer economy could be related to electrics so that's why I threw that in there. He suggested that if it's not getting as much juice, that the spark may be weaker than it should be so it's not burning as efficiently as it could.  No clue on that, but the 'lectrics is now my starting point on issues.  It's been a couple years since I pulled the slides out of the carps and cleaned things up in there so that's also on the list!

Again, thanks guys.

Now to get the stinking lawn mowed so I have time to work on this! It needs to stop raining and making the grass grow.

[nunzio]

I would go through the bike and clean ALL ground to frame connections there is probably more than just the battery ground.

Bad grounds will have you chancing your tail for a long time.

You could also disconnect one sub harness at a time and see if you can find the area that is causing the problem.

Good luck...Alan

[jacksonracingcomau]

The issue with the horns happens even with the ignition switch just turned on and the engine off. The engine starts fine every time so I know it's charging. I suppose that's still pointing to grounds. If the grounding was poor, that would also give me weak lights too.  A guy I work with suggested that the poorer economy could be related to electrics so that's why I threw that in there. He suggested that if it's not getting as much juice, that the spark may be weaker than it should be so it's not burning as efficiently as it could.  No clue on that, but the 'lectrics is now my starting point on issues.  It's been a couple years since I pulled the slides out of the carps and cleaned things up in there so that's also on the list!

Again, thanks guys.

Now to get the stinking lawn mowed so I have time to work on this! It needs to stop raining and making the grass grow.

Only reason I say mpg/idling is different problem is that it starts easily
Normally bad sparks show most at start up.
Not impossible to be connected, just very unlikely IMHE

Clean earths, service & tune, def fit new plugs,

[Kiwi_Roy]

Try measuring the Voltage on the common wires to coils, it should be close to 12V
If it's low trace the voltage back through the wiring towards the battery.

If you measure from the common wire to battery Positive it will indicate the Voltage drop directly.