2008 Breva 750 Charging Issue

[Momo]

I bought this late last year via Cycle Trader from a dealer in western Maryland for 2900 delivered to my door.  Due to weather, - and work I only rode it somewhere around 400 miles since then.  BTW, it came with Givi bags, new tires and battery as well as recent service. 13+ K on the odometer.

Several weeks ago the battery was dead when I tried to ride it to work.  Charged it fully, went for a 50 or so mile joy ride, came home and battery was dead again.  I found the rectifier side of stator/rectifier plug badly corroded.  I removed the rectifier and thoroughly cleaned the connector with my glass bead unit.  Reinstalled, checked charging(14+ V) and went for a ride.  When I got home the battery was dead and the system was not charging.  Output of stator was at least 50 VAC when revved.  Assuming rectifier was bad I ordered one off eBay.  The shop manual had no info on troubleshooting the rectifier.   I installed that, let the bike run with a cooling fan on it and sure enough system was charging at 14+ V.   However, after roughly 10 minutes it stopped charging.  I immediately checked stator output, which was still 50+V and even installed another battery.   The eBay seller was kind enough to refund money for the rectifier but also was unable to troubleshoot it.

Dilemma,  did I get a faulty rectifier or is something killing it?  I definitely need another rectifier but am quite leery whether to install it  or not.  Any thoughts would greatly be appreciated.      Larry

[malik]

Do be aware that that on the Breva's and early V7's of this era, the connector between the regulator and the alternator (the two yellow wires) was sometimes a problem. When mine burned out, I was told it was not uncommon. Apparently resistance builds up in there & it burns out. I cut out all the burnt wire (& the connector) & soldered new wire in - which was fine until I had the separate the engine from the frame. I recommend you replace the whole connector with a more effective type. I don't know whether this helps solves your problem, but it can't hurt. A new regulator doesn't fix a faulty connector on the alternator side. I don't know enough to tell a good connector from a faulty one by looking at it. All the others on the bike of the same type have been working fine.

[Momo]

Do be aware that that on the Breva's and early V7's of this era, the connector between the regulator and the alternator (the two yellow wires) was sometimes a problem. When mine burned out, I was told it was not uncommon. Apparently resistance builds up in there & it burns out. I cut out all the burnt wire (& the connector) & soldered new wire in - which was fine until I had the separate the engine from the frame. I recommend you replace the whole connector with a more effective type. I don't know whether this helps solves your problem, but it can't hurt. A new regulator doesn't fix a faulty connector on the alternator side. I don't know enough to tell a good connector from a faulty one by looking at it. All the others on the bike of the same type have been working fine.

Thanks, that repair is common on old Hondas, especially 750 sohc.  Initial find was a burnt connector on the rectifier side, stator side looked brand new.   New rectifier eliminated that problem but the system stopped charging after 10 minutes or so.  Most likely I will order another rectifier and see if that fails.  Just  don't understand why the new rectifier worked for 10 minutes and then failed.   As mentioned alternator output is good.  Maybe I'll hardwire the new rectifier.   Thanks for the input,  Larry

[Kiwi_Roy]

As Malik says the original connectors overheat and fail, chop them right out and solder the wires or use butt splices just cut the wires if ever you need to remove something.
It might not hurt to take the cover off the alternator and examine where the wires are soldered to the stator, replace the wires if you find they are corroded.
Perhaps the regulator is failing when hot in which case a new one should solve that. Double check the regulators ground connection, if you can't find where that is it wouldn't hurt to add another from the green wires to an engine bolt.
http://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif

[cee2cee]

I had the same issue on my 07' Breva and replaced the rectifier and that solved the problem.  I suspect you got a lemon from eBay.  The one I purchased was for a Ducati.

[Muzz]

As I have never had a problem with mine but...

I believe somewhere sometime someone said that the rectifier has to be earthed to the frame.  Doesn't make sense to me but it may be worth while just ensuring that there is a metal to metal contact just in case.

I usually get at the air filter through the front, so remove the rectifier.  A thin wipe of vaseline (or in my case Lanocote) is used why I replace it, just in case.

Kiwi Roy, have you heard of this?

[Momo]

Thanks for all the responses.  I've ordered another rectifier, hopefully the previous one was defective.  If not, ?????  I have a set of connectors from Vintage Connections, might use them instead of the 2 prong plug.

Kiwi Roy, are you suggesting splicing into the rectifier green wire and running it to ground?

The first rectifier was aftermarket, one I just ordered is likewise.  If it fails,  I'll spring for the extra Ducati rectifier cost.

Appreciate the help

[timonbik]

Did you check to 20amp charging fuse by the battery?  Ask me how i know.  Very easy to short out when boosting, putting clamps on a battery or installing  battery.

[Kiwi_Roy]

Thanks for all the responses.  I've ordered another rectifier, hopefully the previous one was defective.  If not, ?????  I have a set of connectors from Vintage Connections, might use them instead of the 2 prong plug.

Kiwi Roy, are you suggesting splicing into the rectifier green wire and running it to ground?

The first rectifier was aftermarket, one I just ordered is likewise.  If it fails,  I'll spring for the extra Ducati rectifier cost.

Appreciate the help

Only if you cannot find where the ground connection is, you can have as many ground connections as you like, Probably better to ground the blacks on the other side of the connector, I dont believe the regulator chassis needs to be grounded but that won't do any harm.
I am having a similar issue with my one year old V7 at the moment.

As I have never had a problem with mine but...

I believe somewhere sometime someone said that the rectifier has to be earthed to the frame.  Doesn't make sense to me but it may be worth while just ensuring that there is a metal to metal contact just in case.

I usually get at the air filter through the front, so remove the rectifier.  A thin wipe of vaseline (or in my case Lanocote) is used why I replace it, just in case.

Kiwi Roy, have you heard of this?

You may be confusing it with the Ducati Energia's of the 2000 Era, they relied on a ground connection for the current to return to the other end of the alternator coil. The factory made no effort to ground the case properly but relied on a small black wire (half the size of the red wire to the battery) from the battery, Adding a decent short wire from the case to a screw on the engine made use of the main ground wire to the gearbox. I know of at least 3 bikes that let out the magic smoke when the main ground worked loose forcing the starter motor return current to the regulator and back through the small black wire causing it to glow red hot and melt itself into other wires in the loom. Later regulators have 2 dedicated ground wires

[Muzz]

Thanks Roy.

[malik]

As Roy advised, do remove the alternator cover & check the wiring at that end. I had the cover off the 2010 V7 to turn the crank for the tappets, a strong spark jumped out. Found that the insulation on the wires where they disappear into the body was brittle & flaking off. I put a little liquid tape over them, and it's been fine since. Maybe more like plastering over the crack, rather than fixing the problem, but it's working so far.

[Momo]

Did you check to 20amp charging fuse by the battery?  Ask me how i know.  Very easy to short out when boosting, putting clamps on a battery or installing  battery.

Will do, Did not know of its existence,   Thank you

[Momo]

As Roy advised, do remove the alternator cover & check the wiring at that end. I had the cover off the 2010 V7 to turn the crank for the tappets, a strong spark jumped out. Found that the insulation on the wires where they disappear into the body was brittle & flaking off. I put a little liquid tape over them, and it's been fine since. Maybe more like plastering over the crack, rather than fixing the problem, but it's working so far.

I did have the cover off but did not thoroughly check wiring,  Will do that, and thank you

[timonbik]

Will do, Did not know of its existence,   Thank you

My Breva acted similar and that's all it was.  Battery went dead so I boosted it to get it running but soon as i took the cables off , idiot lights came on and bike died.   Ordered a new battery, installed and all was good for about 50 miles, then idiot lights and bike died.   Had the bike trailered home and got on the forum.  Lots of advice from bad rectifier, bad alternator, faulty battery then someone told me about "the" fuse.  Sure enough that's what it was and worst part is that I had a spare with me and could have changed it on the side of the road and rode home.
Cheers, Tim
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[Momo]

My Breva acted similar and that's all it was.  Battery went dead so I boosted it to get it running but soon as i took the cables off , idiot lights came on and bike died.   Ordered a new battery, installed and all was good for about 50 miles, then idiot lights and bike died.   Had the bike trailered home and got on the forum.  Lots of advice from bad rectifier, bad alternator, faulty battery then someone told me about "the" fuse.  Sure enough that's what it was and worst part is that I had a spare with me and could have changed it on the side of the road and rode home.
Cheers, Tim
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Thanks Tim, have you had any problem since?   I haven't had the opportunity to check mine, hoping that is the problem.
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[timonbik]

No, has been fine for the 20,000+ km since.

[Momo]

No, has been fine for the 20,000+ km since.

Thanks for the response.  I hope to have time tomorrow or the next to check out the Breva,   Larry

[Momo]

UPDATE:    and not a good one

As Tim suggested I checked the charging fuse, which was good.  The prongs were covered with a substance that I believe was dielectric grease.  Cleaned the contacts, reinstalled the original rectifier, started the bike and lo and behold it was charging. After 5 minutes or so, the charging system shut down.  I let the bike cool down , restarted and it still wasn't charging.  Anyhow, the scenario reminded me of a problem I had with a Jeep Grand Cherokee( bad ecu that drained the battery when car was turned off)  so I disconnected a battery terminal, which I assume resets the ecu and charging resumed. 

Now it seems as though the ecu is bad or something is telling it to shut down. 

BTW, I've never had a bike with an ecu or even fuel injection.  Newest bike I've ever owned was a 1994 Kawasaki Concours

[Chuck in Indiana]

that I believe was dielectric grease.

That stuff has killed several Guzzis. The gas generated travels through the wiring loom and corrodes relay contacts. *I don't know* if this has any bearing on your problem, but I had a Strada that would quit running when hot until I finally got all the dielectric grease out of all the connectors. <shrug> Sorry, I don't have a wiring diagram.

[Momo]

That stuff has killed several Guzzis. The gas generated travels through the wiring loom and corrodes relay contacts. *I don't know* if this has any bearing on your problem, but I had a Strada that would quit running when hot until I finally got all the dielectric grease out of all the connectors. <shrug> Sorry, I don't have a wiring diagram.

Did you physically remove it or use some sort of contact cleaner?  Did resetting the system cause charging to resume on your bike?    thanks for the input,  Larry

[Momo]

So I drove over to the Piaggio dealer to talk with their tech.  BTW, New Guzzis and Aprillias are gorgeous bikes.  He told me readings between yellow stator wires should be ..2 to .3 ohms and there shouldn't be continuity between yellow wire and ground.  Anyone have any idea if that was accurate info?  I am using a Klein digital meter, readings are shorts across the yellow wires and also to ground.   When charging shuts down the alternator is still putting out 20v at idle and at least 60 when revved.   In my  60 years of working on Japanese bikes I've never seen a bad alternator.   Hope to get this bike back on the road,  Larry

[Chuck in Indiana]

You'll see bad alternators if you continue to work on Guzzis.  Yours is ok, though.. it's the regulator that is the problem. *Disclaimer* I have never worked on one of the "modern" small blocks, and am assuming it uses the same Ducati  charging system.

Did you physically remove it or use some sort of contact cleaner?

I physically removed the grease and used contact cleaner. It had screwed up the "sidestand" relay, which powered the relay that sent power to the coils.
A previous owner decided dielectric grease was a good thing and packed *every* electrical connection with it. Naturally, it never ran again. Another guy bought it, and he couldn't get it running, either. Enter your hero  and with the help of the denizens here on WG had it running shortly.

[Kiwi_Roy]

http://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif
Note the wire colours two greens shorted together, two reds shorted together (may be striped) and a pair of yellows probably no circuit between, you don't have anything else do you?
I think the Voltages you are seeing at the yellows are reasonable, is that with the wires connected or not?
The resistance between yellow wires will be quite low but I don't have it in front of me.
There should be no circuit from yellow to chassis especially if the yellows are not connected.
The reds or striped wires will have some sort of a circuit to the greens, i'm guessing 5,000 - 10,000 Ohms.

[Momo]

You'll see bad alternators if you continue to work on Guzzis.  Yours is ok, though.. it's the regulator that is the problem. *Disclaimer* I have never worked on one of the "modern" small blocks, and am assuming it uses the same Ducati  charging system.

I am assuming the regulator is an integral part of the rectifier.   Is it a separate unit ?    Also, I've been assuming the ecu controls charging.   Like I said earlier, never worked on a bike newer than 1994.  Appreciate the help

[malik]

I thought all (or most) modern regulators are reg/recs. And, in my ignorance, I can't see any reason for the ECU to have an effect on charging. You've an alternator & a reg/rec - what else is needed?

[GonzoB]

Excerpt from Breva manual:



Note the unconnected generator voltage at RPM(s). Note the  connected regulator voltage spec and where measured. Just those measurements should indicate where the problem is.

Gonzo

[Momo]

Thanks Gonzo,   I have those measurements but 14+ at the battery drops away after  5 or so minutes,  AC at alternator remains within specs.  Same result with a new rectifier.   Appreciate the input,  Larry

[GonzoB]

OK, so the alternator and rectifier are working at least at startup. When you say the voltage at the battery drops away, what does it drop to? If you turn off after it drops, does it go back up again on startup?

Gonzo

[Momo]

OK, so the alternator and rectifier are working at least at startup. When you say the voltage at the battery drops away, what does it drop to? If you turn off after it drops, does it go back up again on startup?

Gonzo

Thanks for the input, Gonzo.   Voltage drops to 12.7 and the meter needle neither rises nor falls.   I then disconnect the neg. terminal, wait a couple minutes, reconnect and system starts charging again but will stop after several minutes.

I just got another new rectifier the other day but have not installed it.  Got sidetracked by my El Camino, which needed some long awaited love.     Regards, Larry

[Muzz]

I will be interested in the final outcome, as I am finding the figures somewhat bizarre.

AC figures remain constant..... equals alternator ok.
Charge figures ok for 5 minutes, then fall away. 

This second one is often a symptom of a failing capacitor.....but, to my knowledge there are no capacitors in a regulator.  A bridge diode setup in a regulator I wouldn't have thought would fall away.  Diodes don't usually do that.  May be wrong on that though.  Usually when diodes get electrical constipation and won't pass a current they die completely and don't even scream.  That would then show up as no charge at all. (Actually, it may show up as a half of the sine curve charging?)

I hope it is the regulator Momo seeing as you already have it , but if it doesn't, my suspicion is that a contact for whatever reason, is heating up over that 5 minutes and then breaking contact , whether it be verdigris, dielectric grease or a broken wire.

Best of luck anyway.