Hi members. I started a small fire on my UK 1981 Kawasaki KZ440A. I have two questions to help me get to the root cause behind the reason for the fire.
Symptom - All electrics died during a journey. I'd been on the bike and moving for less than 5 minutes. Prior to the event, no issues. The battery is less than two months old.
Issue - A blown fuse. The fuse was actually a 35A fuse in the place of the 20A fuse.
Attempted fix - Roadside assistance came to my aid after I had checked two things:
1. The battery was ok. It had 13.3V ahead of connection to the charger, which then indicated a full charge within a few minutes.
2. The ignition switch wiring, using a ohmmeter it checked out ok in the Off position and the On position.
Roadside assistance checked the fuse and replaced it. The engine restarted and all appeared good without me riding it. It idled stationary for a few minutes then I switched it off and returned home to get my gear.
The next day I restarted it. Within minutes, the fuse blew again. Naively, I followed the "Get home" advice in the user manual: wrap the fuse in tinfoil and re-insert. A few minutes after restarting the bike, smoke and a small fire started just ahead of the petrol tank. Needless to say the tin-foil fuse was flicked out. Mea culpa. Every day is a school day I suppose, and I was lucky the fire did not lead to a burn-out - I know that.
The fire appeared to be the brown wire leading to the horn. It is damaged from the fire spot into the main wiring loom under the tank. No other wires appear to be affected, except the red/white wire attached to one end of the 35A fuse - The solder betwixt wire and fuse clip has melted, and some burn on the fuse holder at the other side of the 35A fuse. There is some melting of the black electrical tape along the main wiring loom.
I've attached three photos. One of the fuse, one of the front-end of the fire-damaged brown horn wire, and one of the main wiring loom's seared electrical tape.
My two questions are:
1. Is the root cause most likely the rectifier? If so, Would the following be a suitable replacement:
Regulator Rectifier for Kawasaki KH400 KZ440 Z400J Z400LTD Z440LTD (electrexworld.co.uk)
? I've been unable to remove my rectifier yet. The two bolts are very hard to access.
2. Why did the horn cable go on fire do you think? I assume that's 12V therefore not on the rectifier 20A circuit? Could the horn somehow be the root cause?
I noticed before this incident, the full beam is not working. I've checked the bulb and it's ok, but I know the full-beam flasher shares a rocker switch with the horn. Coincidence, I wonder?
If anyone in the forum can help me diagnose things, that would be great. Thank you in advance.
James