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Ignition fire !
Ignition fire !
Lessons learned from the BMW fire.
1. Always carry a fire extinguisher of CO2 type. Precious seconds were wasted running to the car to get the dry chemical fire extinguisher. Also dry chemical leaves a mess to clean up and is corrosive. I've since gotten small CO2 extinguishers to carry on each bike, BMW, GL1200, KLR650. And have mounted a 10lb bottle in the garage. I had/have another dry chemical in the garage but couldn't remember where it was located, hence the sprint to the car.
2. The Airhead does not have a main fuse. My GL1200 has a 30amp right off the battery and the KLR650 has a 20amp. I estimate that the ignition wiring(starter relay->ignition switch->run/stop switch->coil) had 20amps to 50amp current flow. I'd never really looked at the BMW schematics before. I was shocked to see the only fuses in the system are for turn signals, marker, plate, horn, brake but not the headlight or ignition. I will be installing a main 30A fuse.
3. A battery cutoff switch should be on each vehicle. I don't know why I haven't thought of this before. I've raced sports cars and motorcycles in the past and they ALWAYS have easy to reach battery cutoff switches. So much less damage would have occurred if I'd been able to simply reach down and cut off battery power.
This will be a belt and suspenders approach with a main fuse and battery cutoff. But I've learned my lesson.
You'll see I posted a wanted ad for the right combo switch. I'm getting a couple aftermarket switches just to check run, but would like to use the OE.
Edward aka OldCrow
Re: Ignition fire !
https://www.bmwdean.com/6_Volt_Battery.htm
Bill
Barre, MA USA
1963 R60/2 w/ 1955 Steib S500
1973 R75/5
Re: Ignition fire !
To use a battery disconnect on a R100RT it would be needed to interrupt the D+ on the diode board which supplies voltage to the regulator once the alternator is spinning. And possibly the line from the charge indicator light since the light provides current to the field when the bike is started. Would be an interesting experiment.
I see Dean is using SAE power connector for his battery. While this will provide an easy way to plug in a trickle charger, if the bike is running disconnecting the battery will not shut the bike down since those old bikes have permanent magnet generators. Also they don't have electrical starters so the current flow in that SAE should be pretty small recharge flow. I use the SAE connectors on my heated gear and find they are too easy to pull loose so I'd never use one on my main battery power. I'm really tempted to convert my GL1200A and KLR650 over to the BMW style accessory connector. They take a determined pull and they can be plugged in without looking single handed.
OC
- skyler.robbins
- Posts: 227
- Joined: Sat Sep 22, 2018 4:14 pm
Re: Ignition fire !
- srankin
- Posts: 1054
- Joined: Fri Jul 14, 2017 8:45 pm
- Location: Spencerport, NY USA
- Been thanked: 14 times
Re: Ignition fire !
Re: Ignition fire !
Re: Ignition fire !
I took the coils off and measured the ohms with my Fluke 117 multimeter. They both showed within specs as found in the OE Repair Manual. I then placed each coil on a hot plate and raised their temps to about 130degF range and actually the ohms increased as expected. So from that simple test the OE Bosch coils appear good. But I had no way to simulate the bike vibration or check when collapsing the fields. I don't currently have an oscilloscope for further checks.
I've installed 2 Bosch 12-13-1-243-452 coils. They are slightly larger, about 1mm dia and 1/2in longer, but fit the brackets and sliding them back 1/2inch just required moving my Aux tank junction. The coils actually have a higher primary side resistance so the current should be lower. I've rewired Headlight bucket to Coils with 12awg Green. Cleaned up the combination switch and an able to salvage the starter pushbutton and some proper color coded wire, about 3 inches at the switch and the terminal board. The wire between was destroyed. I'll patch in new wire crimped and soldered. I'm picking up a generic handlebar mounted kill switch.
I opened up the main harness from the headlight to the coil area to investigate for collateral damage to other wires. The over heating of the Green/Blue bubbled and melted it's insulation but there appears to be only some insulation stuck to adjacent wires. There is more damage in the headlight bucket where HOT wires looped back and crossed. So there are several in there that need repair.
I'm not getting as much time on the BMW as I would like. My real drop dead date in June 21 2022, when I have an annual summer solstice IBA ride.
OC