1968 CB250 headlight loose cables

[bech]

The 250/350 diagram is almost identical to the wiring colours and components of this bike. Thanks, Steve. It allowed me to solve the problem – I think.

As expected the diagram doesn’t have blk/red - the only wire in the headlight that doesn’t come from the harness. It was attached at the bolt on the top of the fork and had AM scotchloks on both ends. Seems like a PO tried to create ground for the headlight.

There is no emergency switch or a front brake light switch and the rectifier is not attached to the battery box but at the rear fender. The bike has just one fuse - as described in the diagram.

There were 2 green wires with scotchlok. One from the hibeam connector and a loose end and another attaching the wire from the headlight socket to the fixed ring on the headlight rim.

According to the diagram there should be a green wire from the headlight socket to the hibeam connector. So I removed the 2 scotchloks and connected the 2 green wires directly.

I also completely removed the red/blk wire and installed a new one along the harness from the battery neg to the fixed ring on the headlight rim. And everything is working.

If it can stay like this the question is why somebody installed 2 scotchlok rings on the green wire between the headlamp and the hibeam connector?

[e3steve]

Result! Good work Bech. Seems like a PO bodged a repair or perhaps added & tapped-in a spot light to work with main beam?

A twisted 'wire-wrap', soldered and heatshrink tubed is the preferred method of repair; with the right size green heatshrink tubing the repair becomes practically 'invisible'.

• Slide 25mm of heatshrink over the longer end of the wire for repair
  Strip about 12mm of insulation from each of the wires to be joined
  Wrap each stripped conductor around its counterpart, end to end, and twist up tight -- not side by side
  Apply solder to the join -- a hot iron with a fat tip (and a goodly blob of molten solder to aid 'flow') will mean the iron won't need to be in contact for too long, thus reducing insulation meltdown
  Allow the joint to cool a bit, then slide the tubing over the exposed conductor and apply heat, but not with a flame; use a heat-gun or a hot air tip if you have a gas soldering iron

If you need a pictorial of such a repair, let me know and I'll post.

[bech]

Thanks, Steve. It’s pretty well explained.

But there was a twist on the result.

It was working but I wasn’t happy to have a ground wire which wasn’t there originally.
The diagram shows the green wires connected to the headlight rim, which is a ground itself, and no extra ground wire.
So I attached both green wires by the join directly to the ring on the rim making no use of the extra ground wire
It works as well and all the extra terminals and wire are gone.
And the headlight is back to its original condition.

By the way why those headlights weren’t made with a rubber rim in the gap between the chrome rim and the headlight unit to protect the wiring from water?

[e3steve]

Good move on that repair!

No seal around the headlight rims, mate; in fact, I'm not even sure that many m/c manufacturers do so nowadays either.

Most (older and classic) Hondas -- and probably others -- rely upon the steering head bearings for the steered element's electrical grounding. That really goes against the grain for me, as an Electrical Engineer, so I routed a green wire from the headlight's common grounding connector, via the harness tubing and to the CB77's forward frame ground on one of the ignition coils' mounting screws.