Britbike forum Forums British motorcycles in general British motorcycles in general Recognize this wiring harness?

I've had this NOS wiring harness for years, and have been under the impression it is for a Royal Enfield, because I bought it from L&D Motors (now you know how long it has been!):



Not certain what model it is for, but matches one of the standard Lucas wiring diagrams exactly, and certainly is for an alternator model with twin coils and points ignition.

There is a cylindrical connector for the LU34289A (88SA) Lucas headlight switch up front, and a second similar connector for a 63SA ignition switch. To my mind, it is a harness for one of the early twins, but it occurred to me that it might be for just about any make.

Any suggestions?

Thanks,
.. Gregg.

My guess would be C15/B40.

Hi Gregg,


Nah, there's only a Black/White points wire; twin coils/points would have a Black/Yellow as well; so it's either for a single, like Alex says, ... or for a twin with a dizzy?

Also, the Brown/Blue and Brown/White on the left of your picture have the small ring terminals for attaching to an ammeter, so pre-'71.

Hth.

Regards,

Thanks Stuart and Alex. Agreed the ammeter connections indicate pre-1971, and especially so, since I bought it as NOS in 1970 ;-) from L&D Motors.

However, the harness is not for a single. According to the Lucas schematic, the B/W and W leads feed twin ignition coils; with W carrying the (hot) negative lead to both coils. The B/Y and B/W leads one normally sees from/to the contact breakers are carried in a separate harness.

Interestingly, the B/W lead in this harness goes back to the ignition switch to implement an "Emergency Start" function that feeds only the Right Hand ignition coil. Talk about a marginal feature!

Now, here's hoping that someone recognizes which bike it is for, based on the location and general layout of the connectors.

Thanks,
... Gregg

Still looks B40/C15 to me. B/W and W terminals connect to the coil. A separate wire goes to the distributor.

Hi Gregg,



Yeah, that's what I'm seeing on harnesses for dizzy-equipped Triumph twins - one White wire for power to the single coil, one Black/White wire from coil +ve to the points in the dizzy.


In harnesses for later Triumphs (twins and triples), while the wires between coils, points and condensors were clearly assembled separately from the main harness, I don't see that bit available separately with their own part number; they were permanently-incorporated into the main harness by either inclusion in the cloth covering (earlier harnesses) or taping (later harnesses).

That said, that's for Triumphs; when I started doing Beesas, I was surprised to find that, although Lucas made their harnesses as well, while much (like post-dizzy coils/points/condensors wiring) was the same as, or similar to, a contemporary Triumph harness, there were odd little differences too. Possibly this harness isn't for either make, and the maker of whatever it is for had Lucas incorporate their own foibles?

Hth.

Regards,

Do the distributor equipped triumphs have the ignition switch under the seat? Near the battery?

That's the most important detail for mating this harness up with a bike. The ignition switch connector is somewhere in the area below the seat.

.. Gregg

That's what I'm beginning to wonder. I thought originally it was for the original Enfield 500 Twin, since it was their only model with the ignition switch near the rear of the bike. However, that's not the case because its ammeter is in the wrong place for this harness.

Perhaps someone will yet stumble across this thread, and recognize this harness ...

Thanks!
... Gregg

I compared the picture to a NOS C15 road bike harness I have and it does not match. Along with wires not in the correct places for a C15 the wire colors are mostly wrong for BSA unit singles.

Peter

Thank you for comparing and reporting back, Peter. "The thick plottens ..."

...Gregg