Have you changed your bike's electrics to negative ground? The Rita does not need it but ground affects the Rita's connections to the bike's electrics.
Bonneville T140 1976 Electrical Wiring
- Thread starter Migsan
- Start date
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I have not changed the ground to negative, I'm just dealing with the existing wiring. I'm mostly repairing frayed and corrupted wires and connections.
Harness White/Yellow wire -> Rita Black wire,
Rita White/Yellow wire -> battery +ve terminal,
Rita White/Black wire -> one coil -ve terminal, that coil's +ve terminal -> wire -> other coil's -ve terminal,
second coil's +ve terminal -> (Red?) wire ->
. either -> battery +ve terminal ...
. or -> an existing snap connector in existing harness Red wires.
In addition, Rita and 5PU have White/Purple and White/Orange wires:-
. Ideally, obtain more wire with the same two colour combinations (e.g. from British Wiring in the US) to connect the Rita to the 5PU.
. Existing original points wires - Black/White and Black/Yellow - can be used to connect Rita and 5PU; however, ensure great care the same colour original points wire - Black/White or Black/Yellow - connects to the same colour wire - White/Purple or White/Orange - at both Rita and 5PU ... if connections become swapped at one end or the other, while the Rita will still cause sparks at the plugs, the electronic advance/retard does not work.
Connect another (Red?) wire between one of the Rita mounting bolts and the battery +ve terminal. It is most important that one end of this wire is connected only to the battery terminal, nowhere else on the bike; reason is all versions of the Rita except the last (bi-stable version) use the case as part of the protection of the electronics against external Voltage 'spikes', the wire from the case to the battery +ve terminal is part of this protection; if the wire is not present, or not connected correctly, the electronics will be damaged by a Voltage spike.
Finally here, I advise a 5A or 7.5A fuse in the Rita Black wire, ime a convenient place is where the Rita Black wire is connected to the bike's White/Yellow wire.
Usually a 5A fuse is enough; however, 5A can sometimes be too low rated for some ignition coils, blows when the ignition switch is turned on ... causes owner to believe there is a short in the ignition circuit ... However, no short, reason is ignition coils draw an almost infinite current when first energised; this draw falls to normal within milliseconds but some fuses can be sensitive enough to blow ... all that's usually required is a 7.5A fuse instead. I start with a 5A, carry a 7.5A as a spare; you will soon find out which works best ...
Thanks again for the information. I will print and save this.Harness White/Yellow wire -> Rita Black wire,
Rita White/Yellow wire -> battery +ve terminal,
Rita White/Black wire -> one coil -ve terminal, that coil's +ve terminal -> wire -> other coil's -ve terminal,
second coil's +ve terminal -> (Red?) wire ->
. either -> battery +ve terminal ...
. or -> an existing snap connector in existing harness Red wires.
In addition, Rita and 5PU have White/Purple and White/Orange wires:-
. Ideally, obtain more wire with the same two colour combinations (e.g. from British Wiring in the US) to connect the Rita to the 5PU.
. Existing original points wires - Black/White and Black/Yellow - can be used to connect Rita and 5PU; however, ensure great care the same colour original points wire - Black/White or Black/Yellow - connects to the same colour wire - White/Purple or White/Orange - at both Rita and 5PU ... if connections become swapped at one end or the other, while the Rita will still cause sparks at the plugs, the electronic advance/retard does not work.
Connect another (Red?) wire between one of the Rita mounting bolts and the battery +ve terminal. It is most important that one end of this wire is connected only to the battery terminal, nowhere else on the bike; reason is all versions of the Rita except the last (bi-stable version) use the case as part of the protection of the electronics against external Voltage 'spikes', the wire from the case to the battery +ve terminal is part of this protection; if the wire is not present, or not connected correctly, the electronics will be damaged by a Voltage spike.
Finally here, I advise a 5A or 7.5A fuse in the Rita Black wire, ime a convenient place is where the Rita Black wire is connected to the bike's White/Yellow wire.
Usually a 5A fuse is enough; however, 5A can sometimes be too low rated for some ignition coils, blows when the ignition switch is turned on ... causes owner to believe there is a short in the ignition circuit ... However, no short, reason is ignition coils draw an almost infinite current when first energised; this draw falls to normal within milliseconds but some fuses can be sensitive enough to blow ... all that's usually required is a 7.5A fuse instead. I start with a 5A, carry a 7.5A as a spare; you will soon find out which works best ...
I have a question. When I started this restoration project on my 1976 750 Bonnie there was no battery. Also It looks like my brother upgraded to an electronic ignition. The OEM wiring calls for a positive ground. The schematics with electronic ignition that I have been looking at the have a negative ground. How would I know if it has been converted? Appreciate any direction.
Does the bike have the original rectifier (mounted behind the battery carrier, look in the parts book for a picture and/or enter "lucas 49072" into a browser search) and Zener diode (mounted on one of the air filter boxes, again look in the parts book for a picture and/or enter "lucas 49345" into a browser search). If the bike still has those parts, hopefully at least one is marked with "+" or "-" and/or a part number.
You posted the electronic ignition in post #20. Post #21:-
... and I posted Rita positive ground connections in post #23.
They do not ground through their mounting. Simply ensure its negative terminal is connected to the battery's negative terminal, its positive terminal is connected to the battery's positive terminal.However, the Zener diode still grounds through its mounting on the airbox so you will still need to ascertain its ground.
A question on the Zenner Diode bracket. I sandblasted and painted the bracket. Will the heat from the Zenner Diode affect this.
However, the Zener diode still grounds through its mounting on the airbox so you will still need to ascertain its ground.
The Zener on its own does not have a big enough surface area to keep itself cool, Triumph (Lucas?) recommended it be mounted on a heatsink having at least 25 square inches area - standard on any o.i.f., this is one of the airboxes (the timing side one iirc); on "dry frame" models, the Zener is mounted in an aluminium casting with radial fins that acts as a heatsink.
