Electrics : Loom evaluation

A few posts ago, I posted pictures of the two looms I have available, one from the donor bike, and one found in the parts box.
I had initially chosen the parts box option to start with, because it already has the fuse box attached, however, closer examination shows that there are connectors around the headlamp shell area which are not correct.
Maybe this is a YPVS loom, or maybe it’s just been changed beyond recognition by someone in the past.
After careful consideration, I now think it will be better to use the loom from the donor bike as a starting position.
the other loom can provide the fusebox, indicator connections, and headlamp connector.

The donor bike loom has most of the correct connectors, with most of the connectors in workable condition, and most of the wires are the correct colours matching the published wiring diagram.

Notable work needing to be addressed on the donor bike loom.

  • The fusebox is missing
  • There is an extraneous connector for the imposter fusebox
  • There are no connectors for the headlamp
  • There is an extra rogue connector at the front (for the headlamp?)
  • Rear indicator wires are cut short
  • Indicator flasher unit connector has been cut off

I’ll be unwrapping parts of the loom to trace back to the original wires, and crimping new ones in.
(I understand soldering wires in a loom is a no-no, because vibration can sever the joints.)
I have a big box of old looms from many bikes (See parts box), and the connectors and fusebox from the other LC loom, and I think with a bit of attention to detail, I can make this good.

Then it’s about fixing the loom to the bike and routing all the little offshoots. For this, I found these pages from an unknown manual invaluable.

i think of the loom as being in 3 “clumps” of connectors.
The first is the clump which goes in the headlamp shell.
The second is the clump which fits under the tank below the coils.
The third is all the connectors which connect behind and around the battery box, (including the offshoot to the back light and indicators).

Tools for the job.
But first some preparation. For Loom repair, I and going to need some wire, connectors, and tape.
Wire, I plan on reclaiming from some old bike wiring accumulated over the years, and stored in the parts box.
when reclaiming wire lengths, and unwrapping old loom sections, it is noticeable that all connections are crimped. There are no solder connections in a Japanese loom.
Connectors are just a box of bullet connectors I bought when I first built this LC back in the late 80s. I seem to have a lot of double female connectors which I will use as internal crimps rather than soldering.
Tape is not sticky insulating tape.
Tape is a flexible non-sticky tape designed specifically for wrapping electrical looms.

Clump #1 : Headlight
First bit of unwrapping shows that the rogue connector is attached to yellow, green and black wires. This is the headlamp connector for sure.
The rest of the headlamp clump appears to be all present and correct and just needs a clean.

Clump #2 : Under Tank
All the connectors seem to be present and mostly correct here. the temperature sender wire terminates in a male bullet, so I need to make up a female bullet to female spade extension.
Apart from that, it’s all just filthy, so I spend about 30 minutes with some rags and half a can of brake cleaner removing as much grime as I can.
I finish off with a little spray of WD40 into the connectors

Clump #3 : Battery Box
Well, there are some issues with this area. The connector for the Regulator/rectifier has been butchered, (understandably, as it looks like the wires corroded away).
I have found a replacement from another loom with the same coloured wires, so I’ll need to splice that in using the same crimping technique as used on the headlamp connector.
the fusebox connector is an alien one I spliced on 30+ years ago, which needs to be removed, and the good fusebox from the “other” loom spliced in.
Rear indicator wires need to be extended, and the indicator/flasher relay connector needs to be added where it has been hacked out of the loom.
The battery connector wires have been “Hard wired” into the loom, and need to be replaced with shorter wires and bullet connectors.

Leave a Reply

Your email address will not be published.