1977 T-3 not recharging

[across]

Hi out there I have searched the forums and the web without much of a direct answer however my T- 3 is not recharging the battery, the GEN light is on all the time from start up etc.  I have the battery on a trickle charger, however the lack of it recharging limits me for longer rides.  Anyway I know it is a tough question but does anyone have any advice as to what may typically start to fail before I go in an take the rotor out etc. or if this is typically where I need to start.  It seems the rectifier is something that fails so maybe I should start there? It's the Bosch system and I was thinking about buying the whole kit from MG cycle, but if I could save some money and time that would be helpful.  I have no tools to measure the electrical out put - i just know that the charging system is not working, but a drained battery after riding. Any thoughts would be great as a typical place to start. Rectifier - or the regulator - or go into the rotor and brushes. Thanks!!

[guzzisteve]

I would find someone w/a meter to help check diode board and rotor.

[canuck750]

I had an issue with the new fangled regulator that I fitted to my 73 V7 Sport, tried everything imaginable as all, and I mean every damn electrical component was new. I swapped a second new regulator, still nothing, finally in desperation I started to swap back the original components beginning with the old Bosch regulator and viola the battery started charging immediately.

I just went through a similar problem on my 75 750S3, but in this case the battery would just drain down each night. I turned out to be a failed small diode on the Bosch rectifier, swapped another used one in and it is all good.

If you are having any electrical problems I highly recommend buying a new loom and sub-harness kits from Gregory Bender, they are very cheap considering that they are exact matches to stock and they just plug and play. New brushed on the stator if needed and then check the Bosch Regulator and rectifier to trace your charging issues.

[Perazzimx14]

Good luck getting the diode to test out per Guzziology.  I sure the hell couldn't. Bought a new Diode board and it was the same way. Values all over the place, then no values, then some values. After hours, days and weeks of testing and retesting slip rings, brushes, wiring, diode boards, regulators 20 or 30 times, switching alternators with known good ones come to find out the alternator wires were switched. Flipped the wires onto the right terminals and she charges like a dream...with either diode board or regulator.

Check the slip rings with an Ohm meter and verify the alternator is wired correctly before you even fool with the regulator and/or diode board. On the slim chance your diode board is bas let me know and I'll make you a deal on a good one. 

[Chuck in Indiana]

Check the slip rings with an Ohm meter and verify the alternator is wired correctly before you even fool with the regulator and/or diode board.

This. The normal failure is a rotor. Either open or shorted.. they seldom last much past 50K miles.

[radguzzi]

Check the grounds as well.  The gang ground at the left side cover mounting point can be the culprit.

The rotor slip rings need to be checked with the brushes making no contact, thin paper will insulate sufficiently.

Pull each and every connection that you can and clean it, stick it back on.

The last thing that I can offer is that the brushes can bounce off the rotor disrupt good contact if they are set in the vertical position.  Rotate the alternator by one bolt hole, there are three so just move the assembly over one.

Best of luck here, you'll get it.

Rob
 

[jacksonracingcomau]

This. The normal failure is a rotor. Either open or shorted.. they seldom last much past 50K miles.

Radguzzi just beat me as I typed but
rotor usually goes open circuit, charge light never comes on, short is rare

Earth (ground in merkan) for rectifier or regulator is normally why light stays on.

Ground for gaggle of black wires, clean terminals and frame, reattach, esp the tail that earths the rectifier (diode board), he's my main man

[JoeW]

You cannot diagnose electrical systems without a meter, it's like trying to cook without a stove. You can take the advise you get from this forum and replace one piece at a time, you might get lucky. If you're just going to replace everything, buy the Ducati style system from EME, really nice but, a little pricey.

[jacksonracingcomau]

You cannot diagnose electrical systems without a meter, it's like trying to cook without a stove. You can take the advise you get from this forum and replace one piece at a time, you might get lucky. If you're just going to replace everything, buy the Ducati style system from EME, really nice but, a little pricey.

Each to his own, beauty of Bosch system is the warning light, it acts like a meter, you can see if it (a) comes on (b) goes out.
By adding extra ground wire (croc clip) to engine and touching on relevant terminals, your red light acts like a meter, when solved light works, generally you're only cleaning terminals, which is free.

Solid state rec reg if component failure much cheaper than Duc conversion, I do that anyway, saves all the connections that can corrode but for OP connection check will prob solve his issue, red light won't go out. When it does, bike will charge. Weird drains a bit harder (Canuck) but can still be found with patience,

[Kiwi_Roy]

First of all, you haven't changed the charge light to an LED type have you?

Check field circuit
With the key On the charge lamp should light, pull the brown wire off the alternator DF terminal and the light should go out, put the wire back light should come On, lift one brush light should go out again.

Does the blue wire go to the rectifier G1 terminal, it should not go directly to the regulator.

Report back to us



If you can't find a meter get yourself a small 12 Volt test lamp with a couple of wires attached.

With the bike running you should get ~ 10 Volts across the brushes (test lamp bright)

Have you been working on the wiring or did it just stop (just trying to establish if it might be a wire back in the wrong spot)

The brown wire goes to the DF terminal on the alternator, the other brush terminal is grounded although the diagrams don't show it (that's why I asked you to lift a brush with the wire connected)

[Tom]

You definitely need a multi-meter if you're doing electrical work on your bike.  They fairly cheap.

[ed.bremner]

Not had a rotor go.....but had three of the Bosch regulator/rectifiers die.

Now running with a electronic unite from ElectrexWorld:  http://bitly.com/1R6DUI9

Works very nicely.

Certainly helps to have a multimeter, but you can go a long way with a test lamp and some bits to swap in if you can lay hands on them.

Good luck, tell us how it goes

eib

[across]

First off - THANK YOU ALL for the quick and helpful insight.  When I had the bike at the shop replacing coils and the dyna ignition, they said the bike seemed as though it was charging however I never asked them to check it thoroughly.  So before I started ripping anything apart I went through the whole wireing looking for any loose grounds or corroded connections.  I sprayed terminals with deoxit and did find a brown wire on the starter relay that was a little loose - but that was the only thing so far  but I would not imagine that could have been the problem - GEN light still comes on.  The voltage rectifier looks pretty old almost like it may be the original, but looks can be deceiving, I am a bit intimidated to dive into the rotor and brushes on my own -  I have done complete tear downs of BSA s and Triumphs which seem simpler than the guzzi, but I am up for it.

[Chuck in Indiana]

First off - THANK YOU ALL for the quick and helpful insight.  When I had the bike at the shop replacing coils and the dyna ignition, they said the bike seemed as though it was charging however I never asked them to check it thoroughly.  So before I started ripping anything apart I went through the whole wireing looking for any loose grounds or corroded connections.  I sprayed terminals with deoxit and did find a brown wire on the starter relay that was a little loose - but that was the only thing so far  but I would not imagine that could have been the problem - GEN light still comes on.  The voltage rectifier looks pretty old almost like it may be the original, but looks can be deceiving, I am a bit intimidated to dive into the rotor and brushes on my own -  I have done complete tear downs of BSA s and Triumphs which seem simpler than the guzzi, but I am up for it.

Just pick up the brushes and slide something like a paper match under them to isolate them from the rotor. Use your brand new  VOM (sometimes HF has them for free.. (Guzzi content) set it on ohms and touch both slip rings with the probes. You should see roughly 6 ohms.. too lazy to look up the spec.. if it reads open or shorted, it's toast.

[Tom]

 :1:  If you can work on older British bike.  Guzzi's are easier.

[Hahnda]

http://wildguzzi.com/forum/index.php?topic=54522.0

[Tom]

Forgot about that post.  Good info.

[Bazil]

Been having similar issues myself. Check out this diagnostic flow chart from the fine people at Gutsibits in the UK - it might point you in the right direction

http://www.gutsibits.co.uk/pr/TheShed/Downloads/BoschChargingSystemFaultFinder.pdf

[across]

so the latest in the process - pulled the brush magnets and each one would shut the GEN light off when pulled up from the slip ring on the rotor.  Also when I pulled the brown wire off the GEN light would shut off.  Pulled all wires and sanded the contacts and hit them with dioxit.  Magnets are pretty worn to a good curve from the slip rings and I noticed that the ground wire terminal at 11:o'clock (top left) of the plate was missing? traced all ground /earth wires back to rectifier and regulator to be sure nothing was loose and all is good.  My gut tells me that the rotor maybe old and the magnets /brushes need replacement.

[cleatusj]

I have also hooked in a larger bulb in place of the charge bulb and got them to start charging.

[Chuck in Indiana]

so the latest in the process - pulled the brush magnets and each one would shut the GEN light off when pulled up from the slip ring on the rotor.  Also when I pulled the brown wire off the GEN light would shut off.  Pulled all wires and sanded the contacts and hit them with dioxit.  Magnets are pretty worn to a good curve from the slip rings and I noticed that the ground wire terminal at 11:o'clock (top left) of the plate was missing? traced all ground /earth wires back to rectifier and regulator to be sure nothing was loose and all is good.  My gut tells me that the rotor maybe old and the magnets /brushes need replacement.

What you have found out is that you have power to the brushes. It's an electromagnetic alternator. Power comes through the charge light to create the magnetism. What you haven't found out is if the rotor is good. You need to isolate and touch the slip rings with your VOM as I mentioned above *with the power off*. There is no connection to that ground spade, although from memory it's normally toward the bottom.

[Kiwi_Roy]

so the latest in the process - pulled the brush magnets and each one would shut the GEN light off when pulled up from the slip ring on the rotor.  Also when I pulled the brown wire off the GEN light would shut off.  Pulled all wires and sanded the contacts and hit them with dioxit.  Magnets are pretty worn to a good curve from the slip rings and I noticed that the ground wire terminal at 11:o'clock (top left) of the plate was missing? traced all ground /earth wires back to rectifier and regulator to be sure nothing was loose and all is good.  My gut tells me that the rotor maybe old and the magnets /brushes need replacement.

By Magnets I take it you mean brushes, they should be about 5/8" long from memory coppery colour. So we know there's a circuit right through the rotor, it's getting the initial magnetism via the light.
The black wire at 11 o'clock is not really needed as the 11 0'clock brush is grounded.

Chuck in post No 13 mentioned the rotor may be shorted out. You will need a meter to check that
Cletusj suggested a larger bulb to give it a bit more magnetism, I haven't done that but I have run a hot wire from the battery to the brush where the brown wire connects, with the motor spinning at idle that will kick it in the pants at 100% field strength.
You can try that without running, you will get a bit of a flash as you touch the terminal but as long as your wire doesn't get hot it's ok, the flash as you remove the wire is the magnetic field collapsing.
If the rotor is shorted it will draw a lot more current and perhaps let out some magic smoke.

Verify that the blue wire from the lamp goes to the rectifier then to the regulator, that's how the 3 small diodes boost the Voltage to the regulator and turn off the lamp.

Invest in a cheap meter, find one with the diode symbol on one of the switch settings, test each diode in both directions. A flashlight bulb and battery work as well.

[across]

ok - I have a Analog multi meter I used testing home electronics and it has a ohm stetting I haven't used it on my bikes before. I plan to test the rotor this evening when I get home from work - (please excuse my very basic questions here)
 when placing the meter leads ( Black - )  (Red +)  and with the brushes lifted off the slip rings -   I place each lead on 1 slip ring with the key turned on to allow current through but not the engine running? or keep the key off with no current when testing the slip rings on the rotor? 

Another observation I made was that each slip ring had quite a bit of metal wear around them, the copper was pretty coated from being worn down by the brushes.  Again I can't thank you guys enough for the guidance.

[Two Checks]

Measure with key off. IIRC 3-5 ohms. If it's bad do not replace it with one for a BMW. They are similar but different. Different diameter, IIRC.

[Kiwi_Roy]

The analog meter will be fine for testing. It likely won't have a diode test position, I will send you a sketch of how to do that.

[Groover]

There is some information and trouble-shooting in this thread. I'd also suggest on checking the wiring thoroughly before replacing parts. I'd suggest trying to bypass the loom in sections during the test to narrow things down - start with the generator charge wire that goes from the rectifier to the dash (blue wire on the G5, not sure on the T3). Mine had a poor connection at the headlight connector causing the battery not to charge and have a solid red light, which sounds just like your case.

Again, check this thread and at post/reply #43 is what I think you should try.

http://wildguzzi.com/forum/index.php?topic=71398.0

Good luck.

[acogoff]

     One pointer to be aware of is the stock female crimped on wire ends tend to age harden and are become very brittle and a good plan would be to give all of the ones involved some scrutiny and replace if in doubt at all.

[across]

This is a site / article  that I have also found very informative on this matter - although more towards British bikes it does carry a lot of great genera information about electrical systems and troubleshooting etc.
http://www.dansmc.com/electricaltesting.htm

[guzzimike]

My vote goes to faulty Rotor.

Check resistance ( Ohms ) across slip rings. It should be 3.3 or 3.4 Ohms.

Don' t bother cleaning Carbon buildup on the rings, as left by the Brushes. Carbon residue is conductive; after all that is what the brushes are made of...   

I've replaced two Rotors on my CX100; The first at about 40K Miles; the second about 30K miles after that. Both rotors were rewound units..

FWIW, the Alternator's Stator, the Bosch Diode Board ( rectifier ) and Voltage Regulator are OEM.


-

[across]

I did test the slip rings with my meter and they tested out good, so back to scratching my head and then I realized I had replaced the GEN bulb with a 2723 bulb which is a 13.5W 2.3V.  I swapped one of the older bulbs from the control panel for a 2721 which is the standard bulb for this guzzi at 12w 1.2V.   I put that in the GEN light socket. As soon as I did that the GEN light faded after startup and then stayed off with the engine running.  It never came back on while riding.    I then took it out for a ride with the lights on etc. When I got home I shut off the motor  then turned the ignition on.   The GEN light only came on with the key turned but went out right after the engine was started again.I plugged the battery in to my trickle charger to see if the battery had worn down and in less than 10 minutes the battery was at full charge.  I feel like a idiot for sure and always assume the worst when things go wrong.  A lesson learned but because of this there was a lot learned for me and testing my charging system and shared by all of you great folks on this forum - THANK YOU.  I will be sure to give an update if anything changes. Cheers !!!