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Discussion Starter · #1 ·
OK, I guess Lucas and Triumph have parted ways but I have an electrical problem very reminicent of my flat track racing days on a 441 Victor. The alternator doesn't keep up with the demands of normal operations.
Today I rode 25 miles to a PGR staging area, then a mile or so to an event , then 30 miles to lunch. Bonnie worked flawlessly until after lunch, it didn't have enough voltage in the battery to turn the starter motor over. I roll started it, just like the good old days, and rode home about 5 miles.
When I shut it down at home the battery voltage was 10.0v. It's a new (less than 3 hours use) OEM battery! The battery minder is recharging as I write this. The riding I did today was a mixture of city and country. The engine ran for maybe an hour and a half. I'm thinking that if the alternator was dead I wouldn't have gotten as far as I did. That means the voltage regulator (does anyone else remember Lucas' zenner diodes?) could be bad.
My bonnie is factory stock electrically, no added lights, no radios, pure stock. Here's my question to all of you, "Are there any common electrical shortcomings of a 2002 Bonneville? "
 

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pukka
I still have the original battery in my 2001 Bonny and, I
think I'm going to push one more year. This is the longest lived battery I have ever owned.
But anyway, I have not had any problems at all with the
electrics.
If you think you are having a problem with the charging
system , the easy way to test it is to make sure the battery
is fully charged. Start the bike up and get it to running
temperature.
Then put a dc volt meter on the battery . At idle it should
read around 12.5 volts. Slowly bring the revs up to about
4000 rpm. The voltage should increase to around 14.5 volts.
If the voltage is way off , then it gets a little bit more involved.
Good luck I hope every thing checks out OK.
Bill
 

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Discussion Starter · #3 ·
Thanks for your advice, I have been called off to work for the next week so it will be a a while until I can test it.
 

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Discussion Starter · #4 ·
I took Bonnie out for a short ride yesterday with a voltmeter hooked up to the "Battery Minder" cable. Here's what I got:

Before start 13.0v
at idle, engine warmed up 12.1v
at cruise rpm 12.3v

The slight voltage rise (0.2v) from idle to cruise seems to mean the alternator is doing something but not much. It certainly doesn't reach the specified 14.0v.

Where would you all take the troubleshooting logic tree from here?

Thanks
 

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Discussion Starter · #7 ·
The battery is OK, it holds 13v with no load and cranks her up from a cold state with no effort. I visited Houston today and dropped by the Triumph dealer there (there isn't a dealer in San Antonio). The service manager and parts manager agreed that it was 90% sure I had a bad rectifier / regulator.

They want $300 for a new one!!! Does anyone know if a generic substitute will work?

I started this thread with a reference to the old LUCAS Zenner diodes that Triumph and BSA used to use, this is exactly what I remember about the old Triumph's electrical systems. I wish I hadn't thrown out my black "Lucas - Prince of Darlness" T-shirt.
 

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Discussion Starter · #8 ·
There are no listed replacements for the Bonneville but, I cross referenced the part numbers on Bike Bandit and discovered that the TT600 uses the same rectifier / regulator as the Bonneville. Electrex makes a replacement for the TT600 for $120. That will save me $180. Electrex also makes a rotor / generator kit for the TT600, if that is the same part as the Bonneville this info will save someone else about $400.
 

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Discussion Starter · #9 ·
I installed the Electrex rectifier / regulator but it didn't fix the problem. I have a Triumph shop manual, it is really good at showing someone how to disassemble and reassemble everything mechanical but it is very short on diagnosis tools.

Does anyone have the expected resistance / voltage values and diagnosis proceedure for troubleshooting the rotor / stator assembly?
 

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Just replaced the battery in my 2001 Bonnie. It just didn't have the capacity any more. On a cold day 5 cranks and that's all she wrote. Great life for a motorcycle battery! Can't complain about 6 years of service. I would disconnect my battery and put it in my shop to stay warm in winter. Give it a little trickle charge now and then. I guess it helped.

Anyway, I just went out and started my bike with the new battery and these are my metered observations.

(Measured across battery terminals)

Battery connected bike not running = 12.87 VDC

Bike running revs at 1000rpm = 13.30 VDC

Bike running revs at 1500rpm = 14.02 VDC

Bike running revs at 2000rpm = 13.20 VDC

Bike running revs at 6500rpm = 12.90 to 13.00 VDC

Charging voltage seems to drop off at higher rpms ( 6500rpms), but not below 12.90 VDC. (A little difficult to read numbers changing up and down) I have heard that at above 6500rpms the charging voltage seems to drop even further, but I think more things are coming into play at this speed. Increased demand by the HV system for spark may cause a heavy load draw on the charging system. My battery, being new, has probably already been topped up by the alternator and the charging system is now modulating higher or lower depending on demand.

Hope this helps. If you are not getting a voltage reading above 13 VDC after starting, there is a problem


[ This message was edited by: Jimi_X on 2007-03-04 17:05 ]
 

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Discussion Starter · #11 ·
Thanks Jimi_X those numbers help a lot.

I figured out what the five wires connecting to the rectifier / regulator do and was able to measure the raw ac voltage of each leg of the 3 phase alternator. At about 2000rpm I'm getting 13volts on two of the legs and 17 volts ac/rms on the other. After these voltages are regulated / rectified and applied to the system they dropped to 12.3 to 12.6 vdc.

It seemed to me that the alternator system might be overtaxed. In an attempt to shed the system load I unhooked the headlight and, Bingo, the system voltage jumped up to 13.1vdc. That should keep the battery nicely charged. I very seldom ride after dark so I am going to install a switch on the headlight bullet just like my '69 Trophy had. I think the forward facing "position light" will quell any questions from the local constabulary.

It's $700 for a new alternator! At the next oil change I'll open the alternator cover and look for obvious defects. I may take it down to a generator / starter repair shop that I have dealt with before to see if they can work some magic. I also sent Electrex an email hoping they have a stator / rotator repair kit for the Bonnie.
 

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PUKKA,

I'm probably wrong here, but I'm sure I read in a post either here or on the New Triumph Bonneville Board that the raw AC from the alternator is something 70v before passing through the regulator/rectifier.

If you are only getting 13v that doesn't leave a lot capacity for the regulator to do it's job.

You should not have to resort to disconnecting things just to keep the battery charged.

Our man from Sweden would be best qualified to answer this (I think he was the one that mentioned this)
 

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Discussion Starter · #13 ·
Wooly,
I read on another motorcycle maintenance site about the 70 volt ac raw alternator output for motorcycles in general. There is no troubleshooting guide in the Triumph manual to use as a standard. BTW the raw output wires are the three mostly black wires, all in the same row, in the six wire connector (only 5 are used) that plugs into the rectifier / regulator inside the headlight bullet. The other two wires are ground and dc output.
I couldn't agree more that I shouldn't have to unplug things like the headlight to keep the battery charged but $700 for an alternator is a budget buster. The cost will actually go well over $700 as there are also 2 Triumph unique tools required pull the rotor and a gasquet that I will have to purchase. Unplugging the headlight is a workaround until I can find a satisfactory and affordable permanent fix.
I am hopeful that Electrex or my local starter / alternator shop might come through.

Brad
 
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