1985 GS550 - No run after 20 minutes of riding.

[Anonymous]

I have a 1985 GS550. It won't run after I ride it for 20 minutes. After I let it cool down, it starts back up and it's good for another 20 minutes. I need this bike to run for at least an hour at a time. Please help me.

I have:
Changed the oil.
Cleaned connections.
Checked fuses.
Replaced battery.
Replaced spark plugs.
Have new coils, VR coming.

Any help will be appreciated grrrrrrrrrrreatly!!!!!!!!
Thanks.

[MikeW665]

Check this thread out. I think it will help you out, and welcome to the board!

http://www.thegsresources.com/_forum/viewtopic.php?t=22528&highlight=

[KennyJ]

I have an 85 550EF, so here is my thoughts:

Could definitly be the gas cap vent.

Here is what I would do. Purchase an extra spark plug or two, have the tank about 1/2 full of fuel and get ready to ride.

Keep the Gas cap loose or just sitting on the tank (a little masking tape might be used to secure it). Ride in some pattern that keeps you close to home at the 20 minute mark. If the bike keeps running fine, then the vent is your problem. If it dies any way, here is the next step.

Right after it dies, pull the outside sparkplug boots and put one of your new plugs in the boot. Hold the plug body against the bare cylinder fins and crank the engine. Do you see a good hot spark. Is there no spark? You might need a strap to hold the clutch in so you can hold the plug wire and crank it (or bypass the clutch switch, which is easier) since you don't have three hands. If you have no spark, or a really weak one (test your spark before you go riding to see how it looks all cooled off).

Could be a bad ignitor box (not uncommon), but I would run through this easy test first.

Good luck
Kenny

[Detman101]

Could be a bad coil too.


Dm of mD

[Anonymous]

Thanks and some follow up thoughts........

Folks,

Thanks for the quick replies. According to my not so careful tests before my posting, it is not the gas tank vent. I have taken off the gas cap and it still won't start. I have tested for spark and do not get any when warm. I hope to god it isn't the CDI and it is the coils which I should be receiving sometime today or tomorrow.

Please pray with me that it isn't the CDI because I'm a college biker on a budget.

If it is the CDI, any recommendations as to where I could get a good one?

I'm shooting myself in the foot for losing an Ebay auction for a CDI - 108 bucks!

Again,
Thanks!

[Anonymous]

Fixed it.

I changed the VR and coils and now it runs swell.

Thanks :P

[Detman101]

Re: Fixed it.

I changed the VR and coils and now it runs swell.

Thanks :P

Heh, I had a feeling it was the coils.


Dm of mD

[Anonymous]

strange event

It was a very strange event. The battery would jump up to 16 volts when revved, and both coils didn't produce sparks. You wouldn't think that both coils would go bad at the same time. I guess if I thought about it more maybe there is a connection between the VR and the coils failing. Who knows, it's fixed for now at least.

Thanks. BTW - Grrrrrrrrrrrrrreat website!

[Anonymous]

Is this common, for the coils to stop working when the bike is warm? Why is that?