CA160 blows fuse when ignition switch is turned on

[G3]

frollie,

looking at your photo's (#1 specifically), I see what looks like a mashed black wire center top of the image. the wire insulation looks damaged, but the wire itself appears silver?...nevertheless, it looks like it may be exposed. can you confirm?

[DJM]

Well spotted, I'd missed that.

Could well be the cause of the blowing fuses as BLACK wires of that era, on Hondas at least, was a 'HOT' wire and live whenever the ignition was turned ON.

The inner wire would appear to be silver as back then many cables were made with tinned copper strands rather than bare copper, the tinning gives the silver appearance.

Later on, when PVC cables became the norm, cable manufacturers discontinued the tinning process which was a throw back to the days of rubber insulation. The sulphur, or something else in the rubber rubber reacted with bare copper hence the need to 'tin' the strands, the sulphur or whatever apparently didn't react with the tin.

Plenty of 'old' PVC cables still used tinned copper strands for quite while after the 'changeover from rubber.

Hopefully, if you repair this area of damage your problem will be gone but keep us informed.

[frollie]

Dang, good eye. The wire is flattened somehow but it's not exposed. The silver color is just the reflection of the light. Still I'll replace it just to be sure. That is the same black wire as the one that I'm holding in the photo, so it is involved in this thing somehow. It just loops back around from where I'm holding it and goes straight to the ignition coil. Good information about the wire coating and black wires.

[frollie]

Well I'm still going at it.

Here's what I've done:

- Replaced the flattened wire coming from the ignition coil you guys noticed in the previous post.
- Removed the horn completely. Saw no change. Reattached horn.
- Replaced the condenser because I realized the wire I thought was going to the horn was actually going to the condenser. No change.
- Removed the wires going up the handlebars to the high/low beam switch and horn button, removed the sheathing and checked for damage. Fuse test light still went off with the whole switch disconnected. Wires were in great condition so I replaced with new sheathing and put it back.
- Found that one of the wires going underneath the rear fender to the tail/brake light had fallen off its mount and had been dragging on the tire so that the wire was exposed and frayed. I thought for sure this was going to be the solution but after replacing both wires to the tail/brake light the test light still turns on.
- Found that applying the rear brake caused the test light to turn on and off when key is in 3rd position. Disconnected the wires from the switch.
- Put in a new fuse just in case my test light method is inaccurate. Fuse blew when the key was in the 4th position. At this point I can't remember how the problem behaved originally but it seems to have shifted overtime somehow. I've started writing down my results.

Latest Results:

- Headlight will not work with key in any position.
- However, if I take the headlight completely off and wire the green ground wire that is attached to the chrome part of the headlight directly to the neg terminal of the battery and the blue wire directly to the pos terminal, the headlight turns on. But it won't turn on if I wire the red wire to the pos terminal instead. Should it?
- With key in 4th & 5th position, test light is always on.

- With either the headlight completely connected & grounded/mounted and the brake wires are disconnected from the brake switch, or the headlight is completely disconnected and the brake wires are disconnected from the brake switch, these things are true:
1. With key in 3rd position, neutral light is on, test light is off.
3. With key in 3rd position, if brake wires are touched together, test light turns on.
4. With key in 4th & 5th position, test light is always on, neutral light is off.
5. With key in 4th position, if brake wires are touched together, test light becomes brighter.
6. With key in 5th position, if brake wires are touched together, there is no change.

- With the headlight completely connected & grounded/mounted and the brake wires are disconnected from the brake switch:
1. With key in 4th position, if high/low beam switch is set to high beam (down and backward), test light becomes brighter.
2. With key in 5th position, if high/low beam switch is set to high beam, there is no change.

I really don't know what to think anymore.

[frollie]

Wow. I believe I finally got it.

After stripping the wiring down to only the headlight and rectifier I couldn't figure out which was responsible so I replaced them both. The rectifier I got from the guy in Oregon which I linked earlier in the thread. The headlight I got off Ebay from Thailand. It is a non-sealed beam with a changeable light bulb.

After hooking them both up I'm pretty sure the issue was a short inside the original sealed beam headlight. I am no longer blowing fuses and can ride again. However, after my first long ride my headlight went out. I realized that the red wire going into the headlight socket had melted. The wires were thinner than the original sealed beam wires so I cut them off and rewired it using the original wires. They are still getting hot to the touch and I have yet to go on a very long ride so we'll see if they melt again. I was inspired by this post: https://fourwheelforum.com/showthread.php?t=1577

Does anyone know if it's normal for the wires to get hot? Guess we'll see what happens...

Oh, another question. Is it normal for the speedometer light to be off when the headlight switch is set to dim and on when it is set to bright? I put a speedometer bulb in for the first time and it seems odd to me that it wouldn't be on in both positions. Also, I really can't even tell which is position is dim and which is bright but that was true of the original headlight too if I remember correctly...