GS550e "interesting" ignition problem - dies when coils are hot

[Gorminrider]

again, I'll ask: Do you see spark when bike quits working? and Did you test coils voltage drop when cold/working versus hot/not working?

Ignition fuse to coils .8v (kill switch has been bypassed by PO. And there is an extra orange/white wire in the switch loom but no terminal at the connector, anyone familiar with this? 11 wires in the loom, only 10 connectors

This forum is familiar with the archetypal Previous Owners particularly the Kill switch disabled suggests the ignition failed THERE before OR the PO couldn't figure out how to arm/disarm the coils with the relay in place. That's not a good sign.

Quite possible coils are thrashed but the general idea of troubleshooting is to be as sure as you can be that A) they are the problem B) and that replacing them won't just destroy them again due to the reason the first ones failed. It may be the PO destroyed coils experimenting but managed to undo what killed coils such that they were able to sell it to you with bad coils.

But you want to be as sure as you can before buying pricey components.

An aside per .2v drop on just wires end to end : Motorcycles of this ilk tend to use thin wire to keep the harnesses compact and flexible red->key ->orange->to fuseblock is a long loop carrying all current used... likewise ignition Orange/whitestripe or Lights Or/redstripe from the fusebox. so they can have tiny voltage drops carrying sizeable current. (.2v=1.6% of 12.5v ideally should be 0 but acceptable)

Ignition fuse to coils .8v

that's a lot, but does it include the relay...which I assume is still in play? it's little coil I assume is permanently "on" tapped into the ignition circuit and part of the sum. I'd get rid of it for simplicity's sake and it may even be part of the problem

 

[ajh]

thanks guys, really appreciate you taking the time. Hopefully all this detail might help someone else too.

pdqford - im not familiar with trying to test the drop across the coil low tension (LT) positive to negative terminals but I thought I did what you said in previous post. I put the meter across the 2 terminals and made sure the negative (the wire going to points/dynaS) was ground ie. as in when points would be closed. I get 9v because the meter is wired to ground and positive and measuring voltage, not voltage drop. What am i missing?

Gorminrider - stupid question but what relay are you referring to?

Today I checked the voltage drop in total to the coils whilts running and it stayed below 1.5v. I have 12-13V at the coils whilst running so I think its enough. I also wired up the strobe light as i can now run the bike until it fails on idle and watch the strobe. I can see the spark faltering badly on number 2 and number 4 lead as it gets close to dying. I could always hear it but this now shows the spark dropping out. I can also feel the coils getting hot around the terminal ends. So Im now pretty sure both coils are failing when they get hot. When they've cooled the bike runs and idles as sweet as possible

Can you guys recommend a make of coil to buy? Im finding it hard to justify Dynas as its a standard tune engine and they are 4 times the price of regular aftermarket coils.
Any thoughts on resistance? I was thinking the 3ohm would offer a better spark but the 5ohm might run cooler

 

[ajh]

Regarding this extra wire, I had a look at the wiring diagram and it shows the 2nd O/W wire but it then "joins" it to Y/G (is this a relay or something?) As i said on my loom I only have one O/W terminating at the plug but there are 2 in the loom and the diagram shows them as both sides of the switch which makes sense. However, the PO has joined one of the O/W wires to the O wire which looks like its the feed for the lights! I need to try to work out wtf this PO has done as this is definately dropping more than half a volt - Now my head is hurting again!



oohps! wrong wiring diagram see later posts!

​

 

[pdqford]

thanks guys, really appreciate you taking the time. Hopefully all this detail might help someone else too.

pdqford - im not familiar with trying to test the drop across the coil low tension (LT) positive to negative terminals but I thought I did what you said in previous post. I put the meter across the 2 terminals and made sure the negative (the wire going to points/dynaS) was ground ie. as in when points would be closed. I get 9v because the meter is wired to ground and positive and measuring voltage, not voltage drop. What am i missing?

ajh, your not missing a thing! As I understand it you have your meter hooked up correctly to check voltage drop across the coil.
Thanks for explaining the “LT” to me. I’m used to calling it the “primary side” of the coil.

With your meter hooked up to the positive and negative sides of the coil, your meter provides a “parallel” circuit with the coil primary. When you pass current through the circuit most of the voltage passes through the coil, and any coil resistance restricts some of the voltage from going through the coil. That voltage finds its way through the “parallel” circuit, which is in fact, YOUR meter. So your meter displays the voltage that is not being used by the coil, and is the voltage DROPPED by the coil.

In a perfect world all the voltage would go through the coil primary and your meter would show 0.0V being dropped by the coil. But since your meter shows 9.0V being dropped by the coil, there is very little voltage going through the coil. That is why I posted earlier that your coil primary is nearly “open”, as in it doesn’t have a path for the voltage to follow. It is possible for an ohm meter to find a path through the coil if there is just a single strand of wire making contact through the coil because the ohm meter puts out a very minimal amount of current when it tests a circuit. Heck, it can’t even get the coil warm.

But put your bikes full battery current through the coil primary and if there is a week spot in the coil primary it will heat it up and cause some real resistance, which will be measured via voltage drop testing.

Now I have to go rest.

 

[Gorminrider]

right. No relay? I must have mixed you up with another thread, sorry.

Anyways, you've established it's ignition failure. Probably a cooked coil -age alone can kill some of them.
but I'm still a little unsure what burned it out....hoping it's not the doofunny black box that controls the coil...Your coils are meant to work in concert with the device that is pulsing them..and, it's not the primary alone that makes the spark. It's the combination of primary and secondary- a coil is a transformer. You would want to not burn out whatever is pulsing the coils either.

here's a diagram per voltage drops on a headlamp from
http://www.genebitsystems.com/david/...ical/index.htm
you might want to read this too
http://www.genebitsystems.com/david/...onProblems.htm




this method is an example with the negative probe fixed on the negative pole of the battery 16 and as it moves along, it is summing the "voltage drops" towards the positive pole.1..until across the battery poles (16-.1)you get the battery's voltage which =the circuits sum voltage=12.2.... you'll see that the meter would display (12.088-0.121=) 11.967v across just the light (13-..12) The meter has a very high resistance and doesn't have much effect on the circuit as a parallel load which is why and where it is really handy.

 

[Gorminrider]

Regarding this extra wire, I had a look at the wiring diagram and it shows the 2nd O/W wire but it then "joins" it to Y/G (is this a relay or something?) As i said on my loom I only have one O/W terminating at the plug but there are 2 in the loom and the diagram shows them as both sides of the switch which makes sense. However, the PO has joined one of the O/W wires to the O wire which looks like its the feed for the lights! I need to try to work out wtf this PO has done as this is definately dropping more than half a volt - Now my head is hurting again!

​

On these Suzukis, O alone runs from the key to fusebox, feeding the fusebox where after O/W is ignition and, O/R is headlight and dashlamps...memory Y/G is the starter button to solenoid, but possible detour through a clutch switch...
but a PO could certainly do it differently.

 

[ajh]

On these Suzukis, O alone runs from the key to fusebox, feeding the fusebox where after O/W is ignition and, O/R is headlight and dashlamps...memory Y/G is the starter button to solenoid, but possible detour through a clutch switch...
but a PO could certainly do it differently.

So I now have another wiring diagram and it looks like the PO has used a UK 1981 550L right handlebar switch with 2 O/W wires and grafted a different connector plug on to fit my UK 1982 550E loom. Its a tidy job on the connector as it looks stock which doesnt match his other work! More investigation needed to understand WTF has been done!

Thanks Gorminrider!

 

[pdqford]

Regarding this extra wire, I had a look at the wiring diagram and it shows the 2nd O/W wire but it then "joins" it to Y/G (is this a relay or something?);

No, that is not a relay. It is the starter button.
Current comes up that left most O/W wire on your attached diagram and goes to the “E” switch in your attached diagram. That is the E-ngine kill switch. If the E switch is closed, current continues on through the E switch and gets split into two circuits at that splice in your diagram. The current continues on one circuit via the O/W wire to power the ignition system, and also continues on the 2nd circuit to the starter button. When the starter button is pressed current goes through the starter button and on out the Y/G wire to power the starter circuit.

 

[ajh]

Now I have the correct wiring diagram! Still have this mystery of an extra O/W wire in the switch loom connected into the handlebar switch which I suspect is powering the starter button. But it does not exit the loom! Weirdest thing I've seen as the loom 'looks' unmodified apart from the join of O & O/W. Want to avoid cutting up the switch loom outer covering, by default would there be a splice in the loom to the other O/W?
In the diagram I've edited to show my wiring - Weird but it works!

 

[Gorminrider]

That IS peculiar^^kill switch dectivated and the starter button (that activates solenoid) doesn't appear to have power from your diagram unless your orangish swipe mark is an existing wire the PO did? if so, it'll work but no kill switch.*

That line at the top of the switch is an Still have this mystery of an extra O/W wire in the switch loom connected into the handlebar switch which I suspect is powering the starter button. But it does not exit the loom!

Yes that would be the line drawn at the top between and connecting the two switches.They didn't indicate its colour on the diagram. It does not exit the loom. It goes from Kill switch to starter button . In this way, the starter button is part of the "ignition circuit' O/White stripe wire indicates ignition circuit until they used differing colours like the Y/G for solenoid branching off.

It can get confusing, but if you think of any wire mainly Orange wires as being arteries and the others being capillaries it might help..I guess Red has to be seen as "the heart"? Without medical knowledge my analogy is not going to be great but you get what I mean...

*kill switch" mystery. Plainly the PO considered it a problem. it's easiest to think it's just a faulty switch that was not considered to be necessary. Many riders never think of it except when it gets flicked by accident! Not fatal to ignition and probably not the problem unless somehow other circuits were affected by its intermittent failure?

 

[ajh]

That IS peculiar^^kill switch dectivated and the starter button (that activates solenoid) doesn't appear to have power from your diagram unless your orangish swipe mark is an existing wire the PO did? if so, it'll work but no kill switch.*

Very strange, PO has made the join between the O/W and O so they no longer touch the handlebar switch. makes sense to bypass the kill switch but.... firstly there is still a .3v drop even though theres no switch in the circuit now and secondly the starter is still getting a feed from somewhere, it must be from this extra wire that disappears in the handlebar loom. Has to be spliced into same circuit inside the loom without damaging the outer sheath!! Im gonna see if i can get a probe into the switch and test out the wire for continuaty to see where it connects as its bugging me!

New coils on the way for the initial problem

 

[ajh]

New coils fitted and original problem solved!
Still need to look into voltage drops around fusebox and bypassed kill switch but thats a job for another day

If it helps someone in future the summary is - 2 cases of coils failing on late GS550e when they get hot and stalling the engine on idle. Once its stopped, wait about 15 minutes and it will start again no problem. Keeping revs high prevents it stalling in the first place. Coils all check out OK with resistance tests but are failing when hot.

 

[Gorminrider]

Hurray! Ride on!
..but keep an eye (or a hand) on the new coils for awhile. and after your brain has a rest, make another dive into the rabbit hole. What the PO did might be workable but you should be sure. Kill switches are "handy"- while taking your hand off the handlebar and reaching over to a key "in the event.." is not. If I found a kill switch a nuisance, I'd just put a dab of glue on it- not rewire around it.

 

[Guest]

You might want to put a relay in to supply direct battery power to the coils. losses through the kill switch won' t bother a relay, but losses at the coil is a major problem. That is one of the first mods I did on my GS1000 and it has never let me down.