when i switch coil wires the problem switches to the other side, i have no clue why!

[steve_crabb]

I have a 1981 suzukie gs550 and it has four carbs on it, at first only pipes 1 and 2 were running hot and so i thought the carbs might be plugged but i decided to do some other stuff first before i take the carbs off and i sprayed some starter fluid into the carbs attatched to the cylinders that were not working and the bike bogged down and started backfiring! so i then switched the possitive and negative wires on my coils and the problem switched sides! pipes 1 and 2 were cold and 3 and 4 were hot. does this mean that my coils are bad? i have no clue and any advice will be a big help! thanks!
steve

[earlfor]

On each coil, there is a 12v+ power supply wire (usually orange/white)
Disconnect the orange/white wire on the left and right coil. Take a multimeter set to the DC scale 20v and with the ignition turned on, check that you have 12 volts supplied on each orange/white wire.

It sounds like you have a dead harness wire.

Earl

I have a 1981 suzukie gs550 and it has four carbs on it, at first only pipes 1 and 2 were running hot and so i thought the carbs might be plugged but i decided to do some other stuff first before i take the carbs off and i sprayed some starter fluid into the carbs attatched to the cylinders that were not working and the bike bogged down and started backfiring! so i then switched the possitive and negative wires on my coils and the problem switched sides! pipes 1 and 2 were cold and 3 and 4 were hot. does this mean that my coils are bad? i have no clue and any advice will be a big help! thanks!
steve

[steve_crabb]

thanks for the quick reply! i don't have one of those meters, any suggestions on where i can get one for cheap? (i'm in seminary and money is not abundant!) thanks!
ps i have when i pulled each plug i was getting some spark on all four of them. i'm not sure how strong it was, it had some blue but was not a huge spark. i'm not sure if this is valid or not? thanks

[Doctor Shifty]

The coils fire in pairs of 1,4 and 2,3. So when you swap coil wires it should be these plugs that swap.

However, if you have a problem with the ignitor (behind thefuse box) or with the ignition sensing plate (inside the cover near your right toe), what you describe makes a bit of sense.

Check that the wires from the small magnetic sensors on the ignition plate are making full passage to the ignitor unit. It sounds like one sensor or sensor wire is failing and causing either the first hit or the second hit on each coil to lose its pulse. This will have the effect of knocking out one plug on each coil as you describe.

The problem with some of these sensor units is that they can check OK but fail in operation. It's a mystery, even to my old bike mechanic who had the habit of buying them whenever he found one at a wrecker, just in case.

Kim

[Planecrazy]

Even a dirt cheap multimeter can do most of your basic testing ... as little as $20 will buy you a decent one (I got a really nice digital one on sale at Harbor Freight for $20).

Buy what you can afford, but know that having this tool will make diagnosing electrical problems 100% easier!

Good luck!!

[GS550joe]

meter sources

try wally world... they have some for 9 bucks or so... they may not work well for accurate minute voltages but they should show if both side are getting approximately the same voltage.... and they will also show if it is reversed power to the coils.. ask some of these fellows ( or gals) how their bikes' coils are wired... the po could have reversed one coil's connection and that is why it fired the other side when the wired were reversed..

Joe