Help! My 1985GS 550L stops running on long rides...

[avastyematey]

Hi again everyone.
I again need help. Thank you in advance for listening.
Here's my problem/ story from the beginning, its a little long but I figured that more details are better than less.

I purchased a 1985 GS550L earlier this year and have been systematically trying to make my way through all the problems that it has, while still keeping it running and on the road. Most of the stuff has been minor and I have been able to muddle through, but recently one random day the bike died while coming to a stop light, and it opened up a whole can of electrical worms.

The starter wouldn't work and I thought that the starter solenoid had fried, so I replaced that.
The starter button still wouldn't work, so I used the old jump the solenoid trick for a while, which worked fine for a week or so, then whenever I stopped the bike for any reason (gas, go to the store, etc)after running jumping the solenoid wouldn't work, but pop-starting would.

I eventually tracked down the cause of the starter button not working (bad wire) and replaced it.

Now the starter and the solenoid worked and everything was running okay or so I thought...

I was on a ride around some backroads, was riding for about 45/50 minutes, ~50mph cruising speed, slowed down to take a corner and the engine quit on me. Screwed around with the bike for about 1/2 hour and got it running, ran home.

Next day I was running to the parts store and it happens again, same thing, running for a while bike gets warm. cruising along, slow down to avoid some sand and the bike dies. I let it sit for an hour while I walked to the store and back, started it up got most of the way home, slowed down for a stop light and it died again.

I thought that it wasn't pulling a vacuum so I wasn't getting gas flow (petcock was broken when I got it and I kinda rigged it to work but only on vacuum setting) So I replaced the petcock. Didn't help.

The bike did the exact same thing again yesterday, this time I had a sparkplug wrench with me and checked for spark all 4 cylinders were not getting spark. Let it sit for 30 minutes, it started up and made it 99.9% of the way home.

It seems like so long as I only run back and forth on a sub 45minute ride I am okay. I have been running back and forth from my work every day and not having any problems, but as soon as I step out for a longer ride boom, broken down again.

Sparkplugs are fine, gapped correctly. Battery is at 12.8 volts. Still need to check the voltage at the coils.

Now, from everything that I have read on here, and from other sources it seems like it could be an ignition problem? Or possibly coils, though that is less probable because both coils wouldn't fail at the same time, or would they?

Can anyone point me in a good direction / shower me with any advice?? I am getting tired of chasing ghosts.
Help Please!
thank you again
jrt

[Calvin Blackmore]

Hi again everyone.
I again need help. Thank you in advance for listening.
Here's my problem/ story from the beginning, its a little long but I figured that more details are better than less.

I purchased a 1985 GS550L earlier this year and have been systematically trying to make my way through all the problems that it has, while still keeping it running and on the road. Most of the stuff has been minor and I have been able to muddle through, but recently one random day the bike died while coming to a stop light, and it opened up a whole can of electrical worms.

The starter wouldn't work and I thought that the starter solenoid had fried, so I replaced that.
The starter button still wouldn't work, so I used the old jump the solenoid trick for a while, which worked fine for a week or so, then whenever I stopped the bike for any reason (gas, go to the store, etc)after running jumping the solenoid wouldn't work, but pop-starting would.

I eventually tracked down the cause of the starter button not working (bad wire) and replaced it.

Now the starter and the solenoid worked and everything was running okay or so I thought...

I was on a ride around some backroads, was riding for about 45/50 minutes, ~50mph cruising speed, slowed down to take a corner and the engine quit on me. Screwed around with the bike for about 1/2 hour and got it running, ran home.

Next day I was running to the parts store and it happens again, same thing, running for a while bike gets warm. cruising along, slow down to avoid some sand and the bike dies. I let it sit for an hour while I walked to the store and back, started it up got most of the way home, slowed down for a stop light and it died again.

I thought that it wasn't pulling a vacuum so I wasn't getting gas flow (petcock was broken when I got it and I kinda rigged it to work but only on vacuum setting) So I replaced the petcock. Didn't help.

The bike did the exact same thing again yesterday, this time I had a sparkplug wrench with me and checked for spark all 4 cylinders were not getting spark. Let it sit for 30 minutes, it started up and made it 99.9% of the way home.

It seems like so long as I only run back and forth on a sub 45minute ride I am okay. I have been running back and forth from my work every day and not having any problems, but as soon as I step out for a longer ride boom, broken down again.

Sparkplugs are fine, gapped correctly. Battery is at 12.8 volts. Still need to check the voltage at the coils.

Now, from everything that I have read on here, and from other sources it seems like it could be an ignition problem? Or possibly coils, though that is less probable because both coils wouldn't fail at the same time, or would they?

Can anyone point me in a good direction / shower me with any advice?? I am getting tired of chasing ghosts.
Help Please!
thank you again
jrt

so is the battery dying? the type os issue you are having could be caused by a bad or marginal reg rect\stator allowing the battery to drain

a new battery will ( i forget the technical term ) basically recover from being depleted giving a false sense of confidence in the charging system

are you able to runt he diagnostics ont he charging system as described in the manul?

[avastyematey]

I don't know if its the battery, it doesn't seem to be though. Nothing else goes out, just the spark. all lights and indicators are still working, hit the starter button and it tries to crank over.

I am planning on attacking the electrical diagnostics tomorrow.
But I was hoping someone else had a similar problem and would have known a good place to start...

[mostholycerebus]

Extremely common problem on these bikes, one i currently have, and likely some kind of intake problem. After changing the air filter, upgrading the R/R, adding the coil relay mod, changing the battery, and replacing all intake boots and o-rings, mine still does it. Difference is, now I can start it easily when it dies.

After you have done all that, I guess, rebuild the carbs again and make sure you are getting a good deal everywhere? I haven't had time to tear mine down again...

[Kerry]

Don't know if it could be this on yours, but I had a dying-when-hot problem that turned out to be the signal generator. Symptoms were similar to what you describe...

[Calvin Blackmore]

I don't know if its the battery, it doesn't seem to be though. Nothing else goes out, just the spark. all lights and indicators are still working, hit the starter button and it tries to crank over.

I am planning on attacking the electrical diagnostics tomorrow.
But I was hoping someone else had a similar problem and would have known a good place to start...

OK so battery being good it could be an unhappy combination of a hot engine not being readily spun by a marginal starter or one that is poorly ground.

it all comes down to a process of exclusion sadly

I would start with valve adjustment
then carb cleaning checking all rubber hoses as well as assuring tank is clean of course while you have the caarbs off O rings are easy you will most likely need them anyway as they are damned old and in a bad bad spot for longevity ( note ny handsome avatar pic)

I got some from robert barr he is a group member and they are cheaper than OEM I thing Suzuki want 5-6 bucks each.

the electrics on this bike suck in the most extreme and perfect way.
I am on my third reg rect and suspect i need a new stator though mine does pass the voltage test.

So good golly Maguyver sp? another group member with a pretty clean and well rejuvenated bike did have a long thread on here about stalling problems maybe that will help you too....

OH and dload the manual i think basscliif has it hosted

oh and give us a pic or two yah know this bike was as rare as could be when i first found this forum but it would seem that it is taking over with at least a half dozen members owning either an L or E\ES model..

[chef1366]

Sounds to me like the igniter is going out.

[avastyematey]

are signal generator and ignitor the same thing?

[hikermikem]

No, the signal generator is the electronic ignition (points replacement). It's located under the cover on the right side of the engine.

The ignitor is the source for the ignition spark, (handled by the sig generator). It's a black box usually located close to the fuse block/battery.

[avastyematey]

okay cool. I'll check the ignitor with my multimeter tomorrow and see what I come up with. I will keep everyone updated. I'll post images of my bike soon too.

[Steve]

Another thing you can check that is easier and cheaper than the signal generator or the ignitor is your fuse panel. The third fuse from the top is for your ignition circuits. Make sure it's making good connection at both ends of the fuse.

If you can manage to get the bike to die while you are home, check for voltage at the coils. If you don't have it, follow the coil supply wire back to the fuse panel, checking every connection along the way. There is also a possibility that the connection on the back of the fuse panel might be the source of your problem if you have no voltage at the coils.

.

[avastyematey]

Thanks Steve, I checked the fuse box but will do it again. I was thinking about riding around town for 45 minutes or so to get it to shut down and hitting everything with my multimeter.

[avastyematey]

so its been raining all day here in providence, haven't had a chance to check everything out but I did get a free GS750 today!

[Calvin Blackmore]

so its been raining all day here in providence, haven't had a chance to check everything out but I did get a free GS750 today!

good god man
is it raining motorcycles in RI?

[avastyematey]

short answer yes, long answer..... um yes?