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#68801 - 03/03/07 4:08 pm Electrical failure - Alternator or Boyer?  
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mitchp Offline
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Hi Guys

850 Mk IIA, stock apart from Boyer Power Box. Out riding this morning, noticed charge light coming on below 2000rpm (normally only on at tickover). Then indicators flashing very slowly, then charge light on all the time. Turn round & head home, but after 10 miles things start to deteriorate, first hesitating, then misfiring, then backfiring through the exhaust...

Phut! Pop! won't go over 3000rpm , only a couple of miles to go, Phut! struggle to keep it running, Bang! no power, nearly home, Pop! rough as a dog, please keep going, Phut! Pop! Bang! Phut! Silence..... Fortunately 1/4 mile from home, so only a short push.

Won't restart, though it does backfire & kick back. Battery is very low, (headlight like a glow-worm) even though it was fully charged when I set off.

I suspect the alternator has gone AWOL, but before I go pulling things apart I'd like to eliminate the Boyer itself as a possible cause. I've seen postings implying the Boyer needs a healthy voltage to work. If the alternator has failed, would the falling battery voltage alone account for the progressively poor running?

Thanks

Mitch


Minds are like parachutes - they only work when they are open.
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#68802 - 03/03/07 4:28 pm Re: Electrical failure - Alternator or Boyer?  
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L.A.B. Online content
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Quote:
Originally posted by mitchp:
I've seen postings implying the Boyer needs a healthy voltage to work.
That would apply to the Boyer electronic ignition systems rather than Boyer Power Boxes (you do actually mean you have a 'Power Box' and not a Boyer ignition?) but a battery going flat is likely to give the symptoms you describe.
So either the alternator stator or the Power Box could have failed or maybe there is a bad connection somewhere? Or the battery itself could have failed?
Have you recharged it?
What ignition system is fitted?

#68803 - 03/03/07 4:45 pm Re: Electrical failure - Alternator or Boyer?  
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BSA Mark Offline
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Hi,

Here's a sure fire way to isolate the problem;

1) Charge the battery and check with voltmeter

2) Start the bike and measure the battery voltage whlst reving the engine (above 3000rpm) You should see the voltage increase which indicates charging.

If your bike does start, check the wiring to the ignition system and got doen woth path of plug and points wires.

If the bike starts and the voltage doesn't increase at 3000RPM go down the regulator / alternator path.

3) Assuming the bike is running (good ignition system). However you're not seeing an increase in battery voltage at 3000RPM, using an AC volt meter connect to the alternator wires (usually the yellow wires) you should measure a voltage that increases ith RPM's. If you do then new regulator (or wiring fault) if you don't then time to take the engine cases off.

4) Just for sanity though. Shut your bike off. Putt putt shudder. Disconnect the Alternator from the regulator and with your meter on OHMS place measure the across the wires comming our of the alternator this should be low (below 100 ohms) if its open circuit or above 1000 OHMS pull the case for sure.

You may find the wire is worn or broken, even shorting to the engine case. Take care when handling the wires and inspect for poor or worn insulation that could be shorting to chassis.

If you don't have a voltmeter, a quick trip to radio shack and about $10 on the cheapest meter is all you need. OK, Even a light blub and a battery but let me know if you'd like to try the bulb path as I am done typing!

Good luck

Mark

(Lucas was the black sheep of the family)


1971 BSA Thunderbolt
#68804 - 03/03/07 4:51 pm Re: Electrical failure - Alternator or Boyer?  
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mitchp Offline
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Thanks L.A.B. Recharged the battery & it started & ran just fine, so tends to confirm bad running due to low battery. Black box is labelled "Boyer Power Box".

Cursory checks with voltmeter show no increase in battery voltage with rpm, though charge warning light is now working normally again.

No obvious loose connections, but I noticed (because I burned my finger on it)that the Warning Light Assimilator is getting very, very hot in a very short time. Surely this isn't normal?

Are there any quick multimeter-type checks for correct operation of the the Power Box?

Thanks

Mitch


Minds are like parachutes - they only work when they are open.
#68805 - 03/03/07 4:59 pm Re: Electrical failure - Alternator or Boyer?  
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Quote:
Originally posted by mitchp:
No obvious loose connections, but I noticed (because I burned my finger on it)that the Warning Light Assimilator is getting very, very hot in a very short time. Surely this isn't normal?
I would suggest you disconnect the assimilator wires (the warning light will stop working) and re-check volts.

#68806 - 03/03/07 6:22 pm Re: Electrical failure - Alternator or Boyer?  
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mitchp Offline
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Alternator checks out OK with the resistance test (Thanks Mark). I really hope it's not the stator - I only got the primary case oil-tight two weeks ago......!

I've gone through the documents from the previous owner & found the instructions (such as they are...) for the Boyer Power Box. These suggest that the Warning Light Assimilator is not needed & the Box can be connected directly to the warning lamp. Can anyone confirm?

Thanks again

Mitch


Minds are like parachutes - they only work when they are open.
#68807 - 03/03/07 6:53 pm Re: Electrical failure - Alternator or Boyer?  
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I cannot confirm that, but it sounds sensible, and if that is what the instructions say should be done then I see no reason to do otherwise.

-----------------------------

Which Power Box wire/s do the instructions tell you to connect the warning light to?

#68808 - 03/03/07 7:15 pm Re: Electrical failure - Alternator or Boyer?  
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jangg Offline
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Yo!
Good suggestions beyond - often isn't trivial. My experience is bluecopy of yours except me hardly came to a gas station from motorway/highway. In my case it was the battery red connection (earth shocked ) screw unscrewed not quite off (since it couldn't not get completely out due to not enough room to get out). Conclusion in my case - earth was bloody disappearing.

So, check and recheck (connections). Regarding alternatotor - if contact stator/rotor I think it would've been more dramatic. And a very much longer way pushing. But again hard to say.

My 2c

regards
jangg


'73 Commando Basket - new aluminium cyl
'93 Ducati 900 SS

"Better lit a light than cursing the darkness"
(Confucius)
#68809 - 03/03/07 7:19 pm Re: Electrical failure - Alternator or Boyer?  
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mitchp Offline
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Trouble is, the instructions are not Commando-specific and make no mention of the Assimilator at all. It's just a photocopied A4 sheet with a very basic wiring diagram labelled "Triumph/BSA/Norton Twin Wiring" with +ve & -ve earth variants. Relevant text states "White or Red/White (from Power Box) connect to the charging lamp and earth".

On my bike the white from the power box is connected to the white/brown of the Assimilator unit. I'm just not sure if this is correct, since the instructions imply that the Box connects directly to the lamp and therefore the Assimilator is not needed. I just can't believe that the Assimilator is supposed to get so hot!


Minds are like parachutes - they only work when they are open.
#68810 - 03/03/07 7:40 pm Re: Electrical failure - Alternator or Boyer?  
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jangg Offline
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My manual(s) - a Haynes and the Andover Norton - have complete wiring schemes and they say that the assimilator isn't vital. Can be cut off. But charging is essential/vital: If alternator's charging it is some other prob (assimilator is just monitoring the charging). "So what" ? Put a voltmeter (or a micrometer) on the charging circuit, see if there's "life". If 12-13 voltage, you are a lucky owner of a well functioning alternator cool

Remember - the ignition circuit is wired in parallell with the charging one (or vice versa). The Boyer is the culprit if not enough voltage (on the battery). So a shortcut is to instant charge the battery with the prescripted 12-13 voltage and (try to) start the bike. If starting, you have to set free the Boyer. Next step is, as I mentioned, if voltage from alternator.

regards
jangg


'73 Commando Basket - new aluminium cyl
'93 Ducati 900 SS

"Better lit a light than cursing the darkness"
(Confucius)
#68811 - 03/03/07 7:55 pm Re: Electrical failure - Alternator or Boyer?  
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OK now I see, you have the Power Box with an *extra* charge warning light wire (I have now found the wiring diagram), so just devise some means of connecting the white/brown warning light wire that originally went to the assimilator (from the light) to the box white wire. That should do it. The assimilator shouldn't really be connected at all as it would have (originally) been wired to run off one of the alternator AC wires.
--------------------------
This info is for the original Positive Earth system of course.

--------------------------
Addition

You mentioned that the white box wire is connected to the white/brown *from* the assimilator? That white/brown should be the wire to the assimilator from the light.
Is there a green/yellow wire still connected to the assimilator by any chance? I hope not?

#68812 - 03/03/07 9:56 pm Re: Electrical failure - Alternator or Boyer?  
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Before changing wireing connections and removing components,did the bike run ok in the past with the original setup?

There are three available Boyer power boxs for the bike . The three phase is meant to be run with warning lite assimilator if wired for positive ground. 2c


If Norton made an airplane,would you fly in it?
#68813 - 03/03/07 10:24 pm Re: Electrical failure - Alternator or Boyer?  
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Quote:
Originally posted by Kommandokenny:
Before changing wireing connections and removing components,did the bike run ok in the past with the original setup?
If the assimilator has been wired into the system which apparently it should not be -(especially if the AC wire is still connected, although there is no proof of that at the moment) and it has shorted out then it is unlikely that how it ran in the past will be any guide. The assimilator should not be wired in so should be removed

Quote:
Originally posted by Kommandokenny:
There are three available Boyer power boxs for the bike .
Actually there are at least about five possible variations of Power Boxes.

Quote:
Originally posted by Kommandokenny:
The three phase is meant to be run with warning lite assimilator if wired for positive ground.
From the description given by mitchp it does not appear to be the three-phase version, but the single phase + warning light (five wire) control type box.

#68814 - 03/03/07 11:00 pm Re: Electrical failure - Alternator or Boyer?  
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bsatrinor Offline
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mitch----i also have a 74 850 commando----you need the asimilater---if you want the red light to work-----they way it works is like this, the light will stay on, at regular 12v battery voltage, when you rev the engine voltage increases,and opens a set of points inside that can, causing the light to go off, it should not be getting hot----

#68815 - 03/03/07 11:14 pm Re: Electrical failure - Alternator or Boyer?  
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Quote:
Originally posted by bsatrinor:
i also have a 74 850 commando----you need the asimilater---
But do you have a Boyer Power Box with a warning light control function? http://www.classicsolutionsuk.co.uk/catalog/Boyer-Bransden-Power-Box-orderby0-p-1-c-253.html

Quote:
------------------------------------
Boyer Bransden Power Box Single Phase with Charging Light
Part No.: PBOXOO166
Single Phase 12V Rectifier/Regulator. Can be used to convert alternator models from 6V to 12V. Can also be used to replace existing 12V rectifier/regulator (Zener etc.) Allows bike to be run with or without a batttery. Has output for charging light indicator to show when battery is charging.
-------------------------------------


According to the Power Box instructions the warning control light (white) wire should be connected to the warning light. The original assimilator is triggered by AC output from one side of the alternator. There is no connection shown to the Power Box for that in the wiring diagram.

#68816 - 03/03/07 11:57 pm Re: Electrical failure - Alternator or Boyer?  
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I guess the next step is to find out which box he has ?? Or we are speculating.


If Norton made an airplane,would you fly in it?
#68817 - 03/04/07 12:27 am Re: Electrical failure - Alternator or Boyer?  
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Quote:
Originally posted by Kommandokenny:
I guess the next step is to find out which box he has ?? Or we are speculating.
Hopefully mitchp has already given enough information to identify the actual Power Box type? As the different function boxes have different wiring colours (and also by his description of his own wiring instructions).

#68818 - 03/04/07 12:57 pm Re: Electrical failure - Alternator or Boyer?  
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Hi guys, sure appreciate all the help!

Power box is a single-phase with charging light control PBOX00166. (There's also a Boyer ignition, by the way)

Before going any further with anything else, I want to sort out the Assimilator. It's connected into the alternator circuit, it's clearly overheating and probably shouldn't be there at all with the Power Box. Therefore it could well be the cause of the problems.

It looks like when the previous owner installed the Boyer he retained the Assimilator and it's wiring (although with modification to the lamp circuit). It has a Green/yellow connection which has continuity with one of the alternator wires, a red connection with earth continuity and a white/brown connection with continuity to both the warning lamp and the white lead from the Boyer (thus bypassing the assimilator's function?).

Question - am I safe to remove the assimilator & simply tape off the green/yellow & red earth wires?

Thanks

Mitch


Minds are like parachutes - they only work when they are open.
#68819 - 03/04/07 4:07 pm Re: Electrical failure - Alternator or Boyer?  
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Quote:
Originally posted by L.A.B.:


Quote:
Originally posted by Kommandokenny:
There are three available Boyer power boxs for the bike .

Actually there are at least about five possible variations of Power Boxes.

3 ,,Not to count rivets, but, Single phase, Bi phase, [swings both ways??],and 3 phase


If Norton made an airplane,would you fly in it?
#68820 - 03/04/07 4:15 pm Re: Electrical failure - Alternator or Boyer?  
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And of course there are variations.
I guess what I'd like to say, is, it was not that relevant to his problem. [the actual number of box's that is, be it, 3 5 7]. We just needed to know which one he has.

Lets try helping him instead of looking for mistakes in each others threads kk beerchug


If Norton made an airplane,would you fly in it?
#68821 - 03/04/07 4:19 pm Re: Electrical failure - Alternator or Boyer?  
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Am I safe to remove the assimilator & simply tape off the green/yellow & red earth wires?

Mitch, Sometimes you have to just try things and see how it goes. You may have to re-ground the red wire after tapimg off the the others.


If Norton made an airplane,would you fly in it?
#68822 - 03/04/07 5:06 pm Re: Electrical failure - Alternator or Boyer?  
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mitchp Offline
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[QUOTE]Originally posted by Kommandokenny:
[QB] Mitch, Sometimes you have to just try things and see how it goes.

Don't have a problem with that......Assimilator's now in the spares box!
All electrical systems seem to be working normally, AC meter shows alternator output 13.5v at tickover rising to 20.5v at 3000rpm...BUT....no increase in battery voltage. Charge light works fine & comes on if I disconnect an alternator wire, so AC's getting to the Power Box but DC output isn't reaching the battery. So, progress is being made & hopefully this is just a broken wire (spaghetti time!). I'll let you know...... bigt

Regards

Mitch


Minds are like parachutes - they only work when they are open.
#68823 - 03/04/07 6:12 pm Re: Electrical failure - Alternator or Boyer?  
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What is the dc output from the power box at 3000 rpm /

You can disconnect the battery and measure across the red /black wires. It should be 14+ volts at 3000 bigt


If Norton made an airplane,would you fly in it?
#68824 - 03/04/07 7:54 pm Re: Electrical failure - Alternator or Boyer?  
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Glad to hear you have had some partial success mitchp, and now that the box has been positively identified as the single phase (5 wire) PBOXOO166 box.

As far as I know the green/yellow generator AC wire to the assimilator should originally have been disconnected along with the assimilator itself when the Power Box was originally fitted. And it would appear that the assimilator has blown and maybe has been shorting the AC output from the still connected green/yellow wire, hence the lack of charging and very hot assimilator? I don't know if that could possibly have damaged the Power Box electronics in some way or not, if you are still unable to get any output (14.5-15v) from the box?

I would suggest that if there appears to be no other fault in the charging circuit that you phone the Boyer helpline and ask their advice?
And as you live in the UK the box can easily be returned to them for testing. http://www.boyerbransden.com/html/contact.html

I have heard reports that the Boyer Power Boxes are not particularly reliable units.

#68825 - 03/04/07 8:26 pm Re: Electrical failure - Alternator or Boyer?  
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Quote:
Originally posted by L.A.B.:
Glad to hear you have had some partial success mitchp, and now that the box has been positively identified as the single phase (5 wire) PBOXOO166 box.



6 wires,, "now were even buddy" laugh laugh bigt sorry couldn't control myself laugh


If Norton made an airplane,would you fly in it?
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