Motobrick meltdown (the k75 caught on fire)

[wmax351]

Well, my motobrick caught on fire. Electrical in origin. Was in traffic, the horn started going off randomly, then the engine was missing, then it quit, and got some smoke from under the tank. I pulled over, disconnected the battery, and then pulled the tank off and blew out what active flame was there. Looks like the wiring is pretty much toast.


Wondering if it might have been the fan. Shares a circuit with the horn. And turns on in traffic sometimes.

[Chaos]

Wow, that could have easily ended very differently.  You gonna look for a new harness or part it out?

[wmax351]

Gonna go through insurance for now and get an estimate. Guess it's why I pay for comprehensive. Unfortunately I had to push it home for about a mile since progressive wouldn't cover a tow (at least directly pay for it) until after the adjuster sees it, and probably took about the same time or less since I was reasonably close to home (and got my exercise out of the way for the day). They also wouldn't do a tow on just a "mechanical failure" tow either, since there was a fire. So a bit of a catch 22.


Definitely could have been much worse. I was probably like 1 minute or so from just taking my laptop bag and lab-coat and just walking away. Thankfully between the tank insulation and the metal, there's a decent degree of safety before the fuel tank would be at risk.


So far, I think I am looking at wiring harnesses (Chassis, engine, cluster/handlebars), fan (vs modify to new, better fan), Ignition switch (and possibly lock as the key is stuck in it), maybe a switch cluster. The ignition box was exposed to some fire, but not sure how damaged it is. All the electronics may be at risk due to shorts to ground and 12V applied to a lot of things that shouldn't have it.

[Filmcamera]

Oh wow, poor you, I am sorry.  It really happened to me as well last week but I was lucky that I only had two or three wires melt and no actual fire. 


When I did the initial rebuild three years ago I was able to buy a used loom pretty cheaply, less than $100 if I remember rightly, so with any luck you will be back on the road pretty soon.


Best of luck

[The Mighty Gryphon]

Sorry to hear of your misfortune. 

Regarding towing, AAA RV Plus is the way to go.  200 miles, and even covers anyone you are riding with.  I pay about 90 bucks a year, and it covers the family cars as well.  Much better service than the insurance company towing.  The AAA tow truck almost always gets there in under an hour, usually sooner unless it is in the depth of winter when they may have a large number of dead battery calls.

If you decide to rebuild, I have an engine harness in good nick.  If the fan frame hasn't melted, you can use it to mount a much superior Spall fan.

[daveson]

Hi

There have been a few cases of fires and shorts lately.

I guess the fan circuit is not the cause as it is protected from the battery by a fuse. The ignition switch is not protected. Since the key was stuck, that's a hallmark pointing to a short in its circuit. Was the handlebar pointing forward when the horn sounded, or is there a non rounded spot where the ignition positive rubbed against? I spose its hard to see, now that its melted.

A stab in the dark. The ignition positive insulation melted from a short, then melted the horn wiring, causing the horn to sound.

Because of these cases lately, and since my bike is 34 years old and I turn my handlebar too, I'm going to install a circuit breaker on the positive side on my bike. I'll have to put it high on the to do list, so it doesn't fall into the forgotten file.

[wmax351]

Interesting. That would certainly make sense. I'll have to do that when I fix it.

[wmax351]

Well, progressive totalled it and gave me the agreed value. I kept the salvage for 400. I got it running again last night. Looks like the speedo isn't working, so I need to diagnose and fix that. And then I realized that the high beam switch will activate both the high beam and the low beam, so I will fix that by feeding the low beam relay from the normally on post of the high beam relay.

[Martin]

Max I'm pretty sure the low beam stays on with the high beam on the Brick.
Regards Martin.

[wmax351]

Interesting. Mine never did. The h4 overheated and blew when I made it do it while driving on a dark road in nevada. Perhaps that was unique to non-faired bike.

[Martin]

I still have my OEM globe around somewhere I upgraded it about 15 years ago. And it's still going. I've probably just jinxed myself.
Regards Martin.