Hi Michael,
I forget to turn off the headlight from time to time,
This sounds like an incorrect connection at the ignition switch - the headlamp should turn off with the ignition switch;
You'll need to undo the headlamp shell from the fork mountings, so you can get access to the wires connected to the ignition switch.
However, first have a look inside the headlamp shell, confirm that the toggle switch has either "31788" or "35710" either moulded into the plastic case or stamped on a metal part, and a Brown/White(?) wire is attached to either terminal #1 or terminal #4 (the numbers are
very small and moulded into the switch case).
Turning to the ignition switch:-
. when you pull the rubber 'boot' off the back of the switch, you should see three wires (Brown/Blue, White and Brown/White (? - same colours as connected to toggle switch terminal #1 or #4);
. on the back of the switch should be three or four male spade terminals - if three, one physically-connected pair and a separate single rivetted to the switch; if four, two physically-connected pairs rivetted to the switch);
. the White wire and the Brown/White(?) should be connected to the same physically-connected male spade pair, the Brown/Blue wire should be connected on its own to either the single spade terminal or one of the other physically-connected pair;
. Brown/Blue is the supply from the battery; the idea is that it's connected to the White wire and the Brown/White(?) to the lights toggle switch only when the ignition switch is turned to 'on'. :thumb
Regarding the zener, what I did was put an ammeter between the zener and its wire. When I was conducting the test with the old battery, it showed that current was flowing through it.
By definition, it should not have been all the time.
The comprehensive test procedure for the standard Zener fitted to your bike is detailed in
the Triumph workshop manual for your bike, manual page H13, .pdf page 182. It says that the Zener should not conduct at all below 12.75V.
However, as I say, no alternator produced by Lucas is capable of generating the "9-18A @3,000RPMs" that you saw; even if one were, you cannot have a variation of 9A at the same rpm.
I was also watching the volts over the battery with my multimeter. They would both fluctuate rather wildly,
Harbor Freight
where I got the higher-end multimeter.
My understanding from several posts over the years on the BritBike forum is Harbor Freight meters are not protected from external emi (electro-magnetic interference). When your bike's engine is running, emi is generated by the HT. 'Fraid that would account for a lot of the nonsense your meters are showing, which renders them useless as diagnostic tools.
To do the test properly, should I have been watching the volts over the zener instead of the battery?
Doesn't matter where you watch it, the system has (should have) the same Volts everywhere.
The usual and simplest Zener test is to connect a Volt-/multi-meter across the battery, observe the indicated Volts with everything off (~12.5V~13V), ignition on (a little less), engine running. With engine running, increasing the rpm slowly should see Volts rise with rpm to ~15V @ ~3,000~3,500 rpm, stay at that level even if engine rpm rises higher, only reducing when rpm reduces below that limit. While by no means completely comprehensive, that is a good indication the Zener is :thumb
Before condemning the existing Zener, I would check its physical and electrical connections:-
5. Reassemble with dielectric or graphite grease (not ordinary grease because it doesn't conduct either electricity or heat).
I'm wondering about the grease. It bolts onto the airbox. Where would the grease come in?
The grease simply excludes the possibility of corrosion-causing moisture between the Zener itself and its airbox and Red wire connection to battery +ve. Dielectric or graphite grease conduct electricity and heat, ordinary grease doesn't.
I generally don't do anything right the first time,
No worries, we all have to start somewhere.
However, as I say, not only is neither the standard alternator fitted to your bike nor any alternator Lucas made capable of fitting into the physical confines of your bike's primary chaincase capable of generating 18A @ 3,000 rpm, you cannot have a variation of 9A at the same rpm, the first suspect when a meter gives impossible readings is emi, and Harbor Freight meters are notoriously not protected against emi.
arn Btw, you don't need a "high-end" meter for emi protection, even the cheap one I carry on the bike has it ...
What are your electrical abilities and tool kit like?
If the video posted by Rambo above is anything to go by, it doesn't look all that difficult to me.
:thumb
The two commonest types of terminal on your bike are bullets and spades. Bullets specifically require a crimping tool with a half-hex in each jaw, spades require a 'M'-shaped cut-out in one jaw. Don't know whether these are available from Harbor Freight but they're definitely available from
British Wiring (TT85 and PR4 respectively). However, I appreciate that you might find BW's prices expensive, I can point you at British suppliers who not only have those but cheaper tools.
The video of the Podtronic type unit shows how it just connects to existing rectifier wires.If you buy one,it generally states connect to the battery positive and negative but going through the ignition switch will cover it with a fuse if a fault develops in the unit.
Sorry, 'fraid this is A Bad Idea.
As I posted above, Lucas rated the standard alternator for 10.5A @ 5,000 rpm and ~8A @ 3,000 rpm.
Asking the ignition switch contacts to transmit these sort of Amps just to save the cost of a common automotive blade fuse and holder in one of the wires between reg./rec. and battery is not sensible.
If you decide to upgrade the alternator in the future, the arrangement makes even less sense.
Hth.
Regards,
'Mornin' K,