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T3 Cali tail/stop light & charge issues

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moxox View Drop Down
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    Posted: 16 Sep 2018 at 15:17
As a new owner, I'm starting from scratch on this - inevitably a 40 year old bike (esp. Italian) has had some 'interference' with the wiring, but I wonder if the symptoms I have are recognised by someone more experienced (ie anyone else)?

Issue 1) The brake light works fine from both switches - it also illuminates a 'tell tale on the 'instrument panel', the light is properly bright.
I thought the tail light works, but on investigation (because it seemed rather bright) I have found that it also (and only) illuminates the brake light bulb.

In neither case, or even if both tried together, does the other (tail light) filament show any light.
Both filaments are present and correct.
Ideas of where to start looking please?

Issue 2) I've read about the charging light and the alternator needing some revs to start charging, but last night (my first ride at night on the bike) when it was extremely dark, I could just see the faintest glow from the charge light. I've checked the voltage and at 3,000 revs its over 13.5v.
Is this a problem? and if so does it mean dusting down the multimeter?

Many thanks




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Jerry atric View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2018 at 22:06
I thought that brake indicator was a fluid level light. Its blanked off on most bikes cos they are rubbish.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2018 at 22:37
Charging.
13.5v at 3k would seem reasonable. But if the glow remains, then it is possible that one of the three small diodes in the rectifier is not working.

Tail lights.
Are you sure the bulb is in correctly? I'm sure it is, but check the obvious.
This is the wiring diagram courtesy of Carl Allison. Might help to trace wiring. something must be wrong.
As said, the brake warning on the dash is supposed to indicate low fluid level. Now it its possible that the fluid is lower than it should be and when you pump the brake it gets lower so brings the light on. Try adding a drop of brake fluid. On the other hand it might be the result of a previous bodge.
Brian.

Better 5 minutes late in this world than years early in the next.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote moxox Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2018 at 08:49
Thanks for replies.
The brake fluid reservoir cap has got a float switch but it is not connected up at all.
The warning lights do not seem to be standard '75 Cali (apologies for photo, but are these v7?)
The bulb is the correct 2 filament one, and the holder presents the contacts in the right way...I'm afraid it's looking like a wiring issue.
So, on this type of instruments - what is the normal function of the 'LIGHTS' lamp please?
Thanks for diode suggestion - I'll have a look for how to test that too.
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Gianni View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gianni Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2018 at 09:03
That is an 850T/V7Sport dash - very rare and desirable.
 
The "Lights" light should be wired into the sidelight circuit so it tells you when the lights are on.
 
The glowing charge lamp is interesting. The bulb is illuminated by current flowing either way - it is wired to the battery on one side and the charging circuit on the other. The bulb rating is (said to be by some) important as it provides a specific resistance in that charging circuit. Try taking it out of the binnacle and running it without potential (sorry no pun intended) interference from other wires and circuits up there.
 
Given  the 850T dashboard, is it possible you have the earlier 850T charging circuit which (IIRC) has a slightly less powerful stator and some variations in the wiring. 
Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT
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rapheal View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rapheal Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2018 at 09:29
Perhaps entrust it to a professional sparks
or a Guzzi specialist
might save you time in the long run
putting right other peoples bodge ups can be costly
thats where experience counts
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Post Options Post Options   Thanks (1) Thanks(1)   Quote red leader one Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2018 at 14:24
Vise vords glasshopper.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2018 at 16:05
If you can understand the wiring diagram and use that information, so long as you are slow and methodical, you should be able to get to the bottom of it.
If you are not happy doing that, then as advised above, get someone who knows to look at it. Saves loads of heartache later. Clearly a past owner came into the latter category and didn't follow that advice.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote rapheal Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2018 at 16:15
In my profession I spend a great deal of time putting other peoples DIY work right
usually after several others have had a go
if you know how it should be done in the first place, and the materials used, then its a straightforward job
but some clients have run the gamut of every expert in the street and family
often the origional fault has been multiplied and duplicated by idiots having a go at it
same with my bike
other than top oil up pump tyres and clean it, and fit a new windscreen I leave it to Antonio
works out cheaper in the long run

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Post Options Post Options   Thanks (0) Thanks(0)   Quote moxox Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2018 at 15:23
Thanks for the comments - I've been thinking about what others with far more experience have said - as well as doing more research here and elsewhere.
I'm wondering if it's time for a radical re-think. 
I see others have gone for the professional total rewire - with upgraded switchgear, fuse box and the like - obviously loosing originality but hopefully gaining reliability and practicality - I'd welcome any views and advice on what to replace and with what..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swede Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2018 at 16:05
On the stop and tail lights, check the rear lamps earth. It could be earthing through the opposite bulb filament and back feeding to find a path, like the fluid level bulb?   The charge problem just could be part of the same?  If not, then suspect rectifier (or V. control but not so likely).  My bike shows 14.2 V max which is the correct figure I am fairly sure.
swede in the shed
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gianni Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2018 at 17:44
Ah... I've just had a thought.
 
If the brake light is causing  dash light to illuminate, it could be an odd variation on the fuse problem I have explained on another thread round here (which I can't find at the moment but some-one will be along to link it - I hope).
 
Try squeezing each of the various fuse-holder tangs while operating the brake and see if the "warning light" goes away and if the separate filaments work properly. What can happen is a duff fuse contact causes a loop and current goes any way it can to get to earth - often through the charge warning light. It is the third fuse down on the T3 and later models but cannot remember which it is on an 850T as it is 30+ years since I stupidly sold mine - IIRC it has a different four-fuse box?
 
I find electrics very easy to manage but I know others do not. A full rewire is not IMHO the solution. With the exception of the fuse box and corrosion on the multi-way connectors a Guzzi has very reliable wiring. A little logical fault finding with a good multimeter and wring diagram may save you £hundreds and give you the confidence to play with the wiring.
 
What you need is someone sympathetic and experienced who can help hands on...
Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT
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Post Options Post Options   Thanks (0) Thanks(0)   Quote theone&onlymin Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2018 at 19:25
You have to be sure the correct wire is on the correct spade at the LH side of the fuse box. There is a possibility someone may have be there before you so you may.
Cheers
Min
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