Suddenly fouling plugs 1 & 4

[Ions001]

1980 GS1000G / All Stock / ~65,000 Miles /

Last Friday, after picking up my wife from work, the bike ran out of gas exactly as we were pulling into the parking lot for our apartment complex. Since we didn't really have any plans over the weekend, I didn't do the walk over to the gas station until Sunday.

I filled the tank half-way, and everything seemed okay. Then on my way to work Monday morning, I kept loosing power. Not all the way dead, but barely able to maintain 45mph with the throttle wide open. It would come and go in spurts.

Then on my way home, it died completely. I let it sit for a couple of hours, then tried again, same thing. The two middle exhaust pipes were hot (not exaggeratedly), but the two outside pipes were cold. When I pulled the plugs, they were coated in gas and pitch black.

Now, I've had trouble in an old Chevy van (1984 G10) that would experience similar issues whenever I bought gas at this particular 7-11 before, but never had any problems with the bike 'til now.

Is it possible that he's watering down his gas, or something like that? If so, would it permanently damage my bike?

I need this bike on the road, as it's my only transportation. Thanks in advance for any insight anyone may have.

[hp1000s]

Are #1 & #4 on the same ignition coil?

[Ions001]

In all honesty, I don't know. I tried to look at the schematics on BikeBandit.com to see, but I couldn't find it.

I was so set in my mind that it was his gas that I didn't even check to see if there was spark. I'll have to check that after work tonight.

[mark]

1 and 4 do run off the same coil. Could be your coil went bad. Switch coils and see if the problem shows up on 2 and 3.

[focus frenzy]

yep, coil or ignitor/ pickup problem, odds are its the coil.

the 1000G fuel line goes between carbs two and three, if there was water you would find the problem with cylinders two and three first.

[flyingace]

Although cold #1 and #4 would seem to indicate a coil, it seems odd that the coil going bad would coinside with your running out of gas. I would follow the advice of switching the coils to see if #2 and #3 go cold.

Is it possible junk in your tank got into the filters and carbs? If it isn't a coil, I would drain my carbs, clean/replace any gas filters and wash the tank out with clean gas. You may has a totally clogged petcock. You need to make sure that gas flows freely to the carbs on prime.

[focus frenzy]

Although cold #1 and #4 would seem to indicate a coil, it seems odd that the coil going bad would coinside with your running out of gas. I would follow the advice of switching the coils to see if #2 and #3 go cold.

Is it possible junk in your tank got into the filters and carbs? If it isn't a coil, I would drain my carbs, clean/replace any gas filters and wash the tank out with clean gas. You may has a totally clogged petcock. You need to make sure that gas flows freely to the carbs on prime.

there are itty bitty screens on the float needle seats, but any trash should have clogged carbs two and three first as gas has to go by those carbs to get to 1 and 4.

[Suzuki mad]

If I leave my GS1000E sitting in the garage for more than two days she decides not to fire up. I have to remove the vacuum pipe and stick a spare pipe on to the vacuum side and suck allowing fuel to come out from the tank. I have to do this till the bike gets enough fuel and the she fires up on all four cylinders.
Its as if the carbs get an air lock in the vacuum system as the fuel evaporates away. Worth checking the vacuum line for any small leaks?
There is a fine filter on the pet cock inside the tank so this may have got blocked with any remnant rubbish from the bottom of the tank when running dry.
Inside the petcock is a small diaphram which has a bush with a small rubber seal on it. This is what seals the fuel from coming out when the system is not in use. I have a spare pet cock which if left sitting in the normal air the 'o' ring seal sticks making it nearly impossible to get any fluid past it. Have you check the pet cock?
1 and 4 plugs do work from the same coil. If the plugs have gone all sooty I would suspect spark problem. Have you got points or electronic ignition on your version?

Suzuki mad
1981 GS1000E
1983 GSX1100ESD in a lot of bits.

[snowbeard]

I highly doubt it's just the gas, it would foul all four plugs. most likely the coils, or possibly the ignitor. there is a procedure for testing the coils,

here's the advice from Billy Ricks

To test the coils put one probe of the multitester on each of the terminals on the primary side of the coil. You should get 3-5 ohms. Check the secondary windings by placing one probe into each of the plug wires coming from one coil. Those would be 2 & 3 from one coil and 1 & 4 for the other. You should get 30-50,000 ohms for stock coils and 15-20,000 for aftermarket.

the primary side is where it plugs into the wiring harness ;-)

[AOD]

Before everyone jumps on the 'it's the coils' wagon...put a good spark plug in #1 and #4 and test it out for spark.

~Adam

[Ions001]

Oh man!

First off, thanks to everyone for your help!

It looks like my problems are much bigger. A mechanic friend of mine took a look at the bike, and didn't have anything good to say.

Gas is moving fine through the petcock, and to the carbs. When we removed plug #4 it was COATED with oil. We cleaned it and replaced it and turned the engine over a few times. When we removed the plug, once again it was coated.

When I replaced the plug, I put the new plug against the block to check for spark, and the engine started on the other three cylinders, ableit very rough. (EDIT: By the way, there was no spark )

So my buddy seems to think that either the rings are hosed on cylinder 4 and/or the piston is shot. Either way, it's crummy timing. Do either of these di·ag·no·ses seem probable?

[earlfor]

do a compression check on all cylinders. If #4 is THAT bad, I would expect compression to way down compared to the other cylinders.

Earl

Oh man!

First off, thanks to everyone for your help!

It looks like my problems are much bigger. A mechanic friend of mine took a look at the bike, and didn't have anything good to say.

Gas is moving fine through the petcock, and to the carbs. When we removed plug #4 it was COATED with oil. We cleaned it and replaced it and turned the engine over a few times. When we removed the plug, once again it was coated.

When I replaced the plug, I put the new plug against the block to check for spark, and the engine started on the other three cylinders, ableit very rough. (EDIT: By the way, there was no spark )

So my buddy seems to think that either the rings are hosed on cylinder 4 and/or the piston is shot. Either way, it's crummy timing. Do either of these di·ag·no·ses seem probable?