2 Electrical Questions 1983 GS450L Suzuki

[BUSARIDER]

2 Questions :

( 1 ) My headlight and tail light quit working. I have brake lights but no running lights ( headlight and taillight ). What MIGHT the problem be ? Is there a fuse for these ?

( 2 ) My left coil quit firing the other day. I checked it in a dimly lit shop and I can get a spark on the input side of the coil where the positive and negative leads plug up. When I plug the coil up tho it does not fire through the coil I suspect is bad or through the spark plug. I took the coil the bike was running off of and put it on the left side I still had spark at the input side but after the coil is hooked up I still get no fire after the coil. ( that is the good coil ). When I plug the wires into the input side It will spark on the blade connectors and at the spark plug tip at the same time but when I spin the engine over it will not spark at the plug ???

Any ideas ?

[Steve]

Too early in the morning to follow what was happening on #2, so I will just answer #1.

Yes, there is a fuse that handles just the lights. I am not very familiar with the electrics on the twins, they are sometimes just a bit different than the fours. On the larger bikes, there are five fuses and a pair of screw terminals.
Starting at the end away from the screws:
LIGHTS - powers the headlights, tail lights and instrument panel lights
SIGNALS - powers turn signals, brakes, horn and oil warning light
IGNITION - powers coils and ignitor
MAIN - powers the whole bike before the engine is running, protects battery if R/R fails
AUX - ppowers the screw treminals.

Your bike may or may not have those screw terminals.

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[BUSARIDER]

I have only found 1 fuse. The fuse is a main fuse a round glass one. I changed it and it didn't help. I have no clue where the fuse box might be ... I have looked all over the bike and nothing. I just Don't know !

[Killer2600]

I have only found 1 fuse. The fuse is a main fuse a round glass one. I changed it and it didn't help. I have no clue where the fuse box might be ... I have looked all over the bike and nothing. I just Don't know !

In stock form the bike should have a fuse panel with 5 fuses behind one of the side covers. The rectifier/regulator and electronic ignition should be behind one of the covers and in proximity to the fuse panel and battery.

[Killer2600]

I can get a spark on the input side of the coil where the positive and negative leads plug up. When I plug the coil up tho it does not fire through the coil I suspect is bad or through the spark plug.

Too early in the morning to follow what was happening on #2, so I will just answer #1.

No worries, I'm wide awake, read it 3 times over, and still don't get it.

What do you mean you can get a spark on the coil primary leads? where is the spark? At the positive/negative primary coil leads?

The only spark that matters is the one that goes through the spark plugs, if your talking about arcing from connecting the positive/negative leads to a power source on and off and seeing the arc/spark from the connection point then that's not a valid coil test.

[Steve]

Sorry, I thought that all models had gone to the 5-fuse system by 1980.

OK, from that fuse is a red wire that goes to the ignition switch.
From the ignition switch is an orange wire that feeds power to the rest of the bike. One wire that is fed by that orange wire is another orange wire that goes to a 9-pin connector that might be under the tank or in the headlight bucket. That wire will loop back to another pin in that connector. On the other side of the connector, it changes to a gray wire, which goes back to the ignition switch and comes out as a brown wire that feeds the tail light. Back at the loop in the 9-pin connector is a yellow/white wire that goes to feed the dimmer switch on the left switch housing on the handlebar. Coming out of the dimmer switch will be a yellow wire for high beam and a white wire for low beam.

I am at work now, so do not have access to PhotoBucket. I have a diagram with those wires highlighted, which makes it easier to follow them. I will edit this post this evening and add the picture for you.

Just follow the current path with your voltmeter, see where you lose the power, and fix it.

EDIT: OK here is the picture. Just follow the descriptiion above and trace the wires on the diagram. Use your voltmeter along the way to see where you lose your power.



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[BUSARIDER]

ok, here's the deal with the bad side of the coil. The two input wires one positive and one negative. If I have the key switch on when I attach those two wires to the coil it will spark as I am plugging them up at the two blade points on the coil and at the same time as I am plugging them up it will spark at the spark plug . However if I leave it plugged up as I am supposed to it will not fire at the spark plug with me turning the engine over with the starter. Can anyone explain that ?

[Steve]

Sounds like a possibly bad ignitor.

Don't let the term "ignitor" fool you, there is nothing magical about it. All that box does is replace the mechanical points from previous years with a few heavy-duty transistors. There is a test in the manual that uses a flashlight battery to check the ignitor, try that to see if the ignitor is OK.

The electrical connections at the coil are rather simple. There is a power wire that goes to both coils and another wire that goes to the ignitor. When the trigger on the end of the crank spins around past the sensor, it sends a signal to the ignitor to stop current flowing through the coil. When the current stops, the magnetism that has built up in the windings collapses, making the spark on the secondary lead(s). In your case, you see a spark when you connect the wires, so current is apparently going through both wires. However, it also appears that the current is not being interrupted, causing the spark at the plug. If the ignitor checks out OK, check the signal generators on the right end of the crank and all the wiring and connectors between them and the ignitor.

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[pete]

All the 450's to my knowledge just have one single main fuse, although I'm not sure about the late '80's models.

If you still have the glass fuse holder, replace it with a blade type holder, you won't regret it.

Even though the glass fuse appears ok, I've been led astray by them before and removing it often ends up with it falling apart in your hand...

As for the ignitor, if it's faulty, then I believe the '83 and onwards 450's have a common ignition system with the early GS500's.

In '83 they went from mechanical advance to electronic advance, so you can't use any ignition components from the '82's or earlier.