'75 850T Alternator recommendation

[JJ]

What is the groups recommendation for an upgraded / modern alternator for a '75 850T?

...and where can I source one?  Thanks in advance.  For my neighbor Kevin's bike...RE" 2018 Datil, NM winning Raffle Bike. 

[Tom]

Enduralast.  Euromotolectrics.  John's in CO, easy to work with.  https://www.euromotoelectrics.com/searchresults.asp?Search=moto+guzzi

Cheap way is to make sure the battery is up to snuff and change out the bulbs to led's and ride only during the day.  Put the battery on a charger every other week.    

[randy yocum]

I put a Saprisa solid state alternator similar to the  Enduralast  Part # EDL450-ALTKIT105 very nice upgrade many years ago for my 1981 G-5 .It's nice not having those pesky brushes to wear out,and maybe leave you stranded with a dead battery this side of Albuquerque.

[Two Checks]

You consider that an upgrade? You can't ride for long in town with the headlight on for long.

[Tom]

You don't need your headlight on during the day in AZ.  I don't use mine in Phoenix.

[wirespokes]

I haven't found the original alternator to need replacing or upgrading. I've been running this same alternator in my airheads since 1990 and the last three years in the guzzis.  As long as connections are bright and shiny they continue to pump out the juice. After thirty or forty thousand miles it might need brushes replaced. No big deal! A big plus is having the engine in tip top tune so it starts instantly. That will keep the battery happy, and make a battery charger unnecessary. Running a high wattage (like about 20W) parking light during the day can save a lot of electricity, or convert to LEDs.

The other thing that helps longevity of the stock system is avoiding big inertia swings on the rotor that loosen windings, leading to an open circuit. Heavy acceleration and deceleration are hard on it.

[Charles in Lake Charles]

I haven't found the original alternator to need replacing or upgrading. I've been running this same alternator in my airheads since 1990 and the last three years in the guzzis.  As long as connections are bright and shiny they continue to pump out the juice. After thirty or forty thousand miles it might need brushes replaced. No big deal!

I completely agree. On my 3 bikes with the Bosch system, I've had to replace one rotor and numerous wiring terminals . I also run adjustable voltage regulators.

[Testarossa]

Easiest fix is to change out the 180w stator for a used 240w stator from a T3. Makes sense to change to a solid state regulator-rectifier at the same time. Both are cheap changes. Then: change to an LED headlight. These changes get you an extra 80 or 90 watts of charging power and will keep the battery charged in traffic.

[Furbo]

Enduralast.  Euromotolectrics.  John's in CO, easy to work with.  https://www.euromotoelectrics.com/searchresults.asp?Search=moto+guzzi

What Tom said.

 

[JJ]

All good inputs!!  Thanks everyone for your recommendations...

I have formatted and forwarded all these comments and  to my friend Kevin.

[Tom]

The full kit is about $500.     A one time shot at upgrading the charging system.

[Antietam Classic Cycle]

The full kit is about $500.     A one time shot at upgrading the charging system.

Or you can go with the 400 watt kit for $200 less.
https://www.euromotoelectrics.com/EnDuraLast-II-400-Watt-Charging-System-p/edl400-altkit105.htm

[Chuck in Indiana]

Or you can go through the entire electrical system, connector by connector, renew, replace, de oxit, etc. As simple of a thing as a bullet fuse with corroded ends can put a load on the whole system. I"ve seen the voltmeter go from near the red to middle of the scale just by replacing fuses and cleaning up the contacts. Costs nothing except a (very) few hours labor. I've put relays on all the heavy loads on the Lario to save the Tron switches. I just put LED taillights in, and will add an LED headlight today if it comes in the mail. Yeah, that costs about 20 bux, though.. 
I truly think that if the above was attended to on these old Bosch systems, they would quit breaking down around the 50,000 mile mark. (corrosion=heat=failure)

[Antietam Classic Cycle]

Or you can go through the entire electrical system, connector by connector, renew, replace, de oxit, etc. As simple of a thing as a bullet fuse with corroded ends can put a load on the whole system. I"ve seen the voltmeter go from near the red to middle of the scale just by replacing fuses and cleaning up the contacts. Costs nothing except a (very) few hours labor. I've put relays on all the heavy loads on the Lario to save the Tron switches. I just put LED taillights in, and will add an LED headlight today if it comes in the mail. Yeah, that costs about 20 bux, though.. 
I truly think that if the above was attended to on these old Bosch systems, they would quit breaking down around the 50,000 mile mark. (corrosion=heat=failure)

Exactly what I've done on my Convert, plus an adjustable voltage regulator and a "big" battery (ETX30L). No need for more, I'm even able to run heated gear without issue.

[Testarossa]

Or you can go through the entire electrical system, connector by connector, renew, replace, de oxit, etc.

This is great advice but doesn't solve the basic problem: The original T alternator uses the same two-terminal 14-amp stator as the V7 Sport and only puts out 180 watts in the best of circumstances. Update to a 20-amp stator (with the extra Y terminal) and you get 280 watts when over 3000 rpm. Huge difference. There is  a 20-amp rotor to match and the rectifier needs to be upgraded. I bought a used stator on ebay and from Euromotoelectrics a new rotor and reg/rect. I think the whole conversion cost about $175 and an hour of my time. That was 15 years ago and EME prices may be higher now.

[wirespokes]

I didn't know the 850T was lower wattage - but that's how the airheads were till 75, so I shouldn't be surprised. Good advice Testarossa. However, I wouldn't change the rotor since it's slightly larger and will generate more electricity than the newer ones. I sort of recall the machined edge the stator mounts into being a different size, so do check into that. That might or not be a small problem, and if it is, not difficult to fix. Just change the stator, voltage regulator and diode board. Since airheads use the same components, just watch for someone selling their old stuff after upgrading. Or check with Lamontsanfurd on ebay. I could direct you to others as well. Probably cost less than $75 - $100. Don't know new cost, but stators rarely die. Beefier diode boards are available - Emerald Isle is a good one and regulators are cheap. Any regulator from an auto parts store with the same plug configuration will work. Most foreign cars with Bosch systems used it.

[injundave]

Check out gutsibits online. Put in part no. ELA00502. I have been using one of these in my T3 for about four years. It is great and was well worth the money for total reliability and peace of mind.

[Testarossa]

And while you're at it -- get an alternator vent ring. It's a spacer that allows air circulation behind the alternator cover and keeps the three-lead AC connector from melting. I think Harper's has it for about $10, with the longer screws necessary.

[Two Checks]

Quote from: Tom on May 27, 2019, 10:33:43 PM

You don't need your headlight on during the day in AZ.  I don't use mine in Phoenix.

Uh...at night?

Also, Iirc the BMW rotor has a slightly different inner diameter.

[Tom]

" during the day"  I'm almost always in before dark.

[Antietam Classic Cycle]

And while you're at it -- get an alternator vent ring. It's a spacer that allows air circulation behind the alternator cover and keeps the three-lead AC connector from melting. I think Harper's has it for about $10, with the longer screws necessary.

One thing I found out the hard way: on a Convert at least, the alloy cover with vent ring/spacer causes the alt. cover to interfere with the lower fender brace under hard braking. I switch to the later plastic cover and vent ring to prevent that. So, do check to make sure it's not an issue on your Guzzis.

[Testarossa]

One thing I found out the hard way: on a Convert at least, the alloy cover with vent ring/spacer causes the alt. cover to interfere with the lower fender brace under hard braking. I switch to the later plastic cover and vent ring to prevent that. So, do check to make sure it's not an issue on your Guzzis.

Not an issue on my T, so shouldn't affect OP. I wonder why the Convert is different?

[JJ]

Or you can go through the entire electrical system, connector by connector, renew, replace, de oxit, etc. As simple of a thing as a bullet fuse with corroded ends can put a load on the whole system. I"ve seen the voltmeter go from near the red to middle of the scale just by replacing fuses and cleaning up the contacts. Costs nothing except a (very) few hours labor. I've put relays on all the heavy loads on the Lario to save the Tron switches. I just put LED taillights in, and will add an LED headlight today if it comes in the mail. Yeah, that costs about 20 bux, though.. 
I truly think that if the above was attended to on these old Bosch systems, they would quit breaking down around the 50,000 mile mark. (corrosion=heat=failure)

We did that, and replaced the fuse box, cleaned all the bullet fuses, installed a new battery, new starter and new voltage regulator.
We are pretty sure it's the alternator...so he will just have to take the hit and get a new one!

Comment from Kevin yesterday:  I just took the MG out for an 80 mile ride. When I started the voltage meter was reading 12.9.  When I pulled in it was at 11.9.  It had gone as low as 11.5.  So yes, it's the generator.  The problem is the fix is about $500.
I'm thinking about that for now.
K

[Chuck in Indiana]

We did that, and replaced the fuse box, cleaned all the bullet fuses, installed a new battery, new starter and new voltage regulator.
We are pretty sure it's the alternator...so he will just have to take the hit and get a new one!

Comment from Kevin yesterday:  I just took the MG out for an 80 mile ride. When I started the voltage meter was reading 12.9.  When I pulled in it was at 11.9.  It had gone as low as 11.5.  So yes, it's the generator.  The problem is the fix is about $500.
I'm thinking about that for now.
K

To check the alternator, all you have to do is insulate the brushes and ohm the slip rings. Normally they are open when failed, but either open or shorted equals dead. From memory,  about 3 ohms is what it should be?
Oh, and is the charge light working?

[cliffrod]

Did you replace the fuse box with new or good looking used? 

We chased this issue & comparable voltage readings on my V7 Sport- brushes, regulator, nos wiring harness and much more, more.  Finally took good advice, drilled out rivets in my very good looking (but ultimately sufficiently corroded, just like he said it would be....) fuse box, cleaned all well and soldered them back together.  It solved the problem. 

I never got a formal plastic vent spacer for the alternator cover. I installed a washer on each bolt between cover and block to try as a quick fix and never changed it.

[Chuck in Indiana]

Oh, one other thing, JJ.. twice now, I've seen this:
"I've replaced every damn thing in the charging system, and it *still* won't charge.."

"Uhh, the wire that comes from the charge light that powers the alternator.. it's electromagnetic, not a permanent magnet alternator, btw.. is on the wrong terminal. There's an unused one that it's hooked to.. "
Hundreds of dollars down the drain because they didn't know how the system worked. <shrug>

[Antietam Classic Cycle]

We did that, and replaced the fuse box, cleaned all the bullet fuses, installed a new battery, new starter and new voltage regulator.
We are pretty sure it's the alternator...so he will just have to take the hit and get a new one!

Comment from Kevin yesterday:  I just took the MG out for an 80 mile ride. When I started the voltage meter was reading 12.9.  When I pulled in it was at 11.9.  It had gone as low as 11.5.  So yes, it's the generator.  The problem is the fix is about $500.
I'm thinking about that for now.
K

It doesn't have to cost nearly that much even if all of the components are defective.
$200: https://www.euromotoelectrics.com/product-p/edl1-altkit105.htm
400 watts for $300: https://www.euromotoelectrics.com/EnDuraLast-II-400-Watt-Charging-System-p/edl400-altkit105.htm

Even with a new charging system wiring harness from Greg Bender it wouldn't be $500. The "bootstrap harness" that Greg sells is worth adding too - it doesn't matter if the warning light works or not then.

Don't know if it's been mentioned, but <grounds> as in, make sure everything that supposed to grounded is and that the ground point is free of paint/powdercoat/etc.

[wirespokes]

Just because the alternator isn't working doesn't mean all of the components (stator, rotor, diode board, regulator) need replacing. There is a way to troubleshoot the system and replace only the bad component.

The most common failure is the rotor and after that is the diode board. And then there's the leads, connections and charge light.

If you're not familiar with the system, here's a detailed write-up from an electronics guru on how it works and how to sort it out. The components are arranged differently on a guzzi, but it's the same stuff.

http://bmwmotorcycletech.info/trbleshootalt.htm