coils were wired like on the diagram that I showed with the power box.
White wire from the BB I connected to the W/Y wire that says ignition coil again from the harness diagram.
To be clear about "W/Y wire that says ignition coil again from the harness diagram", there are two female spade terminals, originally one to each coil negative terminal with points; your BB e.i. White wire is connected to one W/Y female spade and the other is insulated?
Worked really well with the ground wire but the signals are still crossed and the frequency of the turn signals still very high.
"signals ... still crossed" is a connection fault.
With two turn signals working together "frequency of the turn signals still very high" is likely a faulty relay and/or incorrect bulb resistance:-
. Original relay was called "8FL"; however, as usual, Wassell have screwed up and made life difficult for everyone by making two versions in different physical sizes ... If you have either one of these or an eBay cheapie, I advise ditching it for a
Lucas 9FL, it fits in the same mounting bracket as an 8FL but is ime more robust.
. 12V turn signal bulbs must have a resistance of approximately 7 Ohms each.
I don't have any of the small wire connections on the R/H switch you mention.
Your image showed that; that is why I advised buying some useful terminals and a crimping tool.
What would have made my previous post clearer was:-
... which is an unused Harris switch cluster:-
. Front brake switch is top left of the image.
. White/Blue wire is supply to both the kill switch and the front brake switch; as you have posted this is the same on the switch on your bike, where your "Trust Lucas" 'wiring diagram'

says "L/H switch", inside the headlamp shell, connect:-
.. the other end of the switch White/Yellow to the main loom White/Yellow;
.. the other end of the switch White/Blue wire into the White wires - this will be a Sleeve Connector with White wires, including one from the ignition switch.
. Only connect the other end of the switch Brown wire to the main harness Brown wire if your switch cluster has the front brake switch shown, otherwise insulate the end of the switch Brown wire inside the headlamp shell.
. If the switch cluster on your bike is wired the same as my image, the plain White wire is connected to the White/Red wire at one of the black push-buttons:-
.. If you do not intend to use the push-button as an additional headlamp flash button, I advise simply cutting the terminals off the ends of both wires inside the headlamp shell.
.. Otoh, if you do with to use the push-button as an additional headlamp flash button, inside the headlamp shell, connect the switch White/Red into the headlamp main Sleeve Connector (Blue/White wires) and the switch White wire into a Sleeve Connector with White wires including one from the ignition switch.
Finally here, the bullet terminals shown in my image are available from Vehicle Wiring Products -
W Crimp Type 4.7mm Bullet and
a matching crimping tool; for information, they fit the standard bullet female connectors - Autosparks "Sleeve Connectors", VWP calls them
"Snap Connectors".
[Stop lamp] Still not working
Even if your right-hand handlebar switch cluster does not have the front brake switch, the stop lamp should still work from the switch by the rear brake lever, shown as "Stop Switch" at the right-hand end end of that "Trust Lucas" 'wiring diagram'.
front brake switch
I can´t find it not even in the revised replacement parts book
Not shown in any parts book, probably because it was not available separately from the switch cluster.
Tried to connect to the blue and white but when I present the button on the R/H switch it burned the fuse from the battery negative. But the headlight is not working anyway so could be due to some other wrong connection.
34419. I had a spare white wire that I had connected to the white and red but when I hot wire to the 7# still no head light
This is
White wires are (should) be 'live' only when the ignition switch is on, the ignition switch connects Brown/Blue from battery -ve to the White wires:-
. Your bike's "headlight is not working" because, although you have connected the left-hand handlebar dipswitch Blue/Yellow supply wire to the 34419 switch terminal #8, terminal #8 is supplied from terminal #7 when the 34419 lever is fully to the right, and you have not connected anything to terminal #7 because the crappy Wassel Lucas 'wiring diagram' you are using does not say to connect anything to terminal #7.
. If you connect random "spare" wires and expect electrics to work, you will be disappointed regularly. From above, 34419 terminal #7 requires a White wire specifically connected electrically to the ignition switch, probably through a multi-way Sleeve/Snap Connector inside the headlamp shell.
. In addition to the ridiculous Wassel Lucas 'wiring diagram' you are using, I suggest the one in
the Triumph workshop manual covering your bike, the correct diagram is on manual page H22, .pdf page 191.
. Neither of the diagrams show the White/Red wire from the right-hand handlebar switch cluster, because White/Red is the Lucas colour code for electric-start and twins never had an electric-start until the 1980's. The reason the switch clusters have a White/Red in reality is they were originally for the T160, which does have an electric-start.
. If you are confused by my suggestion to use the White/Red wire from your bike's right-hand switch cluster as a headlamp flash button, forget it; verify with the Ohms setting on your multi-meter that the White wire into switch cluster supplies
only the button with the White/Red wire; if so, simply cut off the existing terminals from the switch cluster White and White/Red wires.
Tested the continuity with the voltmeter and the kill switch seems to be working fine between the white/yellow R/H switch wire and the white/blue R/H switch, they are connected to the white/yellow and white wires from the harness in the same order.
Yet I can only get a spark when I check the continuity with the voltmeter between the black and white wire or black and yellow wire
BB (and clones like Pazon, Wassell/Vape and Sparx) e.i. for twins and singles incorporate a major testing

... after the "Transistor Box" is powered up, unless the Box electronics 'detect engine movement' (rising and falling Voltages from the "Stator" through the Black/White and Black/Yellow wires) within a few seconds, the Box switches off the coil(s) supply (the Black wire; the Box switches it back on when it 'detects engine movement') ... Bransden alleges this is to stop the coil(s) draining the battery but ime it is just a pita, and his e.i. for triples do not have the 'feature' (nor do Lucas Rita nor any of the Tri-Spark e.i. ...

).
The way to test for HT sparks is: connect a plug to one of the HT leads and lay it on the cylinder head, ensuring the plug has a good earth; with the Transistor Box and coils powered (connected to the battery either directly or through the switches), touch either the Box Black/White or Black/Yellow wire to a part of the bike, you should see a stream of HT sparks at the plug.
I confirmed the ground wires and they seem to be passing in to the engine correctly when tested despite the powder coat through the bolts. I got the one in the headlamp, the one on the engine head, another I fitted under the coils metal tray and the last one over mudguard stay under the seat.
This is a mistake, by-and-large British bikes - particularly one as new as 1976 - do not have "ground wires". Before '79, the network of Red wires in a standard British bike harness are the primary electrical connection between components and the battery +ve terminal, they
avoid the electrics having to rely on bits of bike for part of the circuits. The Red wire ends with (mostly) ring terminals were for attaching specifically to the mountings of components that 'earthed' through their mounting - e.g. rectifier, Zener, original bulb holders. As you have replaced the points with e.i. and you (should) have attached wires to the turn signals mountings, the only components that still 'earth' through their mountings but do not have Red wires attached are the oil pressure switch and the spark plugs, is why there is a Red wire "on the engine head".
"the one in the headlamp" attaches either to the headlamp bulb holder or a loop rivetted to the headlamp shell bottom front? If the latter and the headlamp shell is rusty under the loop, it will not work as an electrical connection.
"under the coils metal tray" was probably the one for the condensers, originally beside each ignition coil.
However, never anything electrical on the "mudguard stay under the seat" so this is a mistake.
Connected the blue/white and blue yellow like you described. Already had the blue/yellow on the 8# position but the there is still another connection available on the main loom wich I used to connect the remaining blue /yellow that comes from the L/H switch cluster.
This is

again. Look at the Triumph workshop manual wiring diagram, follow the Blue/Yellow ("UY") line from the lights switch "(OFF SIDE HEAD)" to "DIP SW.", there is not (and cannot be) "another connection available on the main loom" - either you have mistaken the wire colours or, if the main loom your are using is a Wassell Lucas one, regrettably they are poor quality, you will need your meter to ascertain which are the correct Blue/Yellow wires to connect lights switch terminal #8 with the dipswitch.
On the harness diagram the three wires come described like R/H switch
The Wassell Lucas diagram is not for your bike, it is for a '73-'75 T140, TR7 or T120, with the earlier handlebar switch clusters - look basically-similar to your bike's right-hand switch cluster but have a short black lever instead of your bike's red lever, right lever is the dipswitch, left lever is for turn signals; they connect to the main loom with bullets and sleeve/snap connectors, not AMP pin connectors.