iTOTAL electrical failure

[megrimsrex]

Hey my name is John,
my 79' R65 has got a total electrical failure. I turn the ignition switch and nothing happens- no lights, no rpm gauge, no starter.
i went through most of the wires and they all seem to be in useable condition. fuses are good. battery is good.

my question is what could cause such a problem ? how do i go about finding the malfunctioning electrical componants if the bike will not turn on at all. any ace electricians out there have a workable algorithm for troubleshooting such a problem. im in a bad spot here and i need help ill be looking forward to any advice at all.

thanks guys.

[Bob_Roller]

Ignition switch, or associated wiring is a good place to start.

If you have a multimeter, get it out and electrically check out the system.

With an old bike loose or corroded connections are a common source of electrical problems, and at times quite frustrating to locate.

If you have a wiring diagram, and know how to read it, start tracing the wires to the ignition switch from the battery.

Where abouts do you call home, one of us here may be in proximity to you ?

[megrimsrex]

im currently in hawaii. i have an electrical diagram and i check out all the wires there all fine. what i dont know how to check is the switch itself. how is that done ? i am thankful for your help.

[Bob_Roller]

You are going to have to gain acess to the switch itself.

As best as I can tell from my wiring diagram, there should be 4 wires attached to the switch, if I remember correctly, they should be push on terminal ends.

The large red wire is the 'hot' lead from the battery, check to see if you have 12 volts there, if you don't, you have a problem with the wire from the battery.

The other three wires should be : grey, green, and a green wire with a violet spiral band around it.

I don't know how you want to procede from here, my suggestion would be to remove the positive lead from the battery, so you don't get the 'shower of sparks trouble shooting method' .

With the switch turned to the 'ON' position, you should have continuity between the red wire and all three of the other wires.

If you don't, there's a strong possibility that the switch is suspect.

I would not suggest spraying a cleaner into the switch like contact cleaner, it removes the lubricant in the switch, and it's not a happy switch afterward. Personal experience at work here.

You said you reside in Hawaii, you have a good possibility of having corroded connections in your wiring harness, due to the 'salt air' environment.

[Justin B.]

Check engine kill-switch.  Things look pretty dead when it's in the kill position OR if defective...

[Bob_Roller]

I checked that on my R65, and with the kill switch off, the headlight still works, at least on an '81 model !!

[Jon_P]

also check all grounds, the juice has to be able to flow and wont if you dont have a proper ground. start with a volt ohm meter and start at the battery for power, go to the fuse, check for power on both sides, that will that ot the kil switch and chcek for power on both side of that switch, then it leads you to the ignition switch. checking the battery to see if it takes a charge and holds one.

be very careful if using a battery charger for a car charging and using it to supply power to you bike, it is far better to get a battery charger that is made for a bike.

[Bob_Roller]

The flow of electricity goes from the battery to the ignition switch, then through the fuse, then to the kill switch.

In short, a lot of wires to check !!!!

[megrimsrex]

when the kill switch is in off position the HUD lights on the dash still used to light up only the ignition/engine electronics would die. fuses are good and every ground i found so far is good. im still having trouble with the ignition switch though it is very dificult to remove.

[megrimsrex]

oh... also i got a brand new battery its as good as they get. fully charged and holds it well. thanks guys

[Ed Miller]

I like test lights better than volt meters for testing for power at different points.  A couple of years ago I was tracing something on my Triumph, and my volt meter showed battery voltage at one point in the chain, but it was not even enough to light a 12 volt lamp.  It turned out to be a fuse that was failing.  I'm still not sure just why the volt meter showed power, except that they are very sensitive.

I still have the home made test lamp I made in 1985 or so, which is only amazing because I've probably moved a dozen times since then.  

[Bob_Roller]

Ed,

You can have one strand of a wire left intact when the others are broken, and still get a voltage reading, or show continuity, but the instant you put a load on it, it fails again.

I havn't seen it too much on motorcycles, but in aviation, where a pin or terminal end is crimped onto a wire, that is a very common failure point that I've seen with my 30 years or so of 'chasing' electrical problems on comercial aircraft.

There is  an electrical device known as a 'megger', that can tell you if the wire you are testing, is failing under load.

I've had several occasions to use another handy tool, it's called a time domain reflectometer (TDR), it will give you a precise dimension from the point at which you are testing a wire, to where it is broken, that is a real time saver !

[Justin B.]

Ed, a good VOM will show a load to the tested circuit in the multiple megohm range while a test light puts whatever load on the circuit according to the wattage of the bulb.  Since the test light actually causes a significant current flow it will often show up a high resistance connection where a VOM will not...

[vestandpants]

hi megrimsrex,

ive had a host of problems with the electrics on my '79 r65 since buying it in 2003 which is one of the reasons why im restoring it.

as previously suggested check the earth points.

check the stability of the connections to ignition switch and the same of the electronic start switch (the screw that holds it on corrodes and strips if you are not careful)

also check the block connections under the tank. they suffer corrosion and i have had them fail on me. remember to take one out at any one time. they are colour coded but always be cautious to be on the safe side.

lastly, has the bikes electrics been altered in any way? for example, spot lamps on the over-riders (engine bars) or an aftermarket battery cut-off switch. mine was and it caused me a few headaches and scary moments when negiotiating a right-hand bend and the engine cut-out because the previous owner wasnt a good electrician    so check any spliced wiring for corrosion too

v&p

[Justin B.]

Bob, I used to use a cable tester (TDR) in computer network troubleshooting.  They were really neat and seems I remember they would indicate a short or open and then tell the number of feet of cable between the fault and where the tester was inserted.  The point you brought up about crimped connection failures is the reason I pretty much crimp and solder the majority of connections.  I've never used a megger but when I was in Army aviation there was one of the maintenance facilities at Ft. Hood (main base) that had one.  We would ship an airplane over there if needed, seems I remember it was usually for a short or elusive insulation breakdown...

I have been spending time this week cleaning up electrical connections, etc., in our Volvo 244.  Seems all European machinery is plagued with corroded connectors and grounds once they get some years on 'em.  The Volvo is especially prone to breakdowns in the fuse panel and a yearly wire brushing and application of grease to connections is almost mandatory.