Firing out of one cylinder

[navuud]

Hi guys, I should say that I am new to the site ergo hello everyone!

About a month ago I purchased a 1981 GS650 from a friend of mine for $400, his only words to me were - "it won't start, and I'm leaving town, take it"

This is my first bike and my mechanical skills are mediocre at best, but heres what I've done.

After hauling the bike over to my backyard I hooked it up to a battery charger, a day later and we've got power! I tried starting it and nothing happened, checked the spark plugs and compression - the spark plugs needed replacing so I did that, and the compression was between 140-160 (according to the manual that's ideal).

After this I was able to start it, however with some trouble so I took out and cleaned the carbs, and now i've got it running, HOWEVER only one of the exhaust pipes is getting hot, I suppose that tells me that its only firing out of one cylinder. Am I looking at sticky valves? Coils? any suggestions would be greatly appreciated.


Edit: When you're sitting on the bike, the second exhaust pipe closest to the engine is the one that is heating up.

[koolaid_kid]

Welcome to the GSR. Excellent job at posting in the correct area, we appreciate it. BassCliff will be along with his mega welcome, but in the meantime go to his site and start looking at some diagnostics and stuff. You can also get a Service Manual there if you don't have one.

http://members.dslextreme.com/users/bikecliff/

[JEEPRUSTY]

Check both wires for spark by placing a plug in them and cranking with it against the block. If you get a nice fat spark on both then its probably a carburetion issue. Maybe the idle circuit is not clean enough.

One cylinder may be running super rich dues to a failed petcock diaphraghm. One carb has a vacuum line attached to operate the petcock.

I assume all Suzuki bikes had vacuum petcocks.
I assume your compressions readings are equal for each cylinder.

[chuckycheese]

Check both wires for spark by placing a plug in them and cranking with it against the block. If you get a nice fat spark on both then its probably a carburetion issue. Maybe the idle circuit is not clean enough.

One cylinder may be running super rich dues to a failed petcock diaphraghm. One carb has a vacuum line attached to operate the petcock.

I assume all Suzuki bikes had vacuum petcocks.
I assume your compressions readings are equal for each cylinder.

Just out of curiosity, JEEPRUSTY, have you ever owned a motorcycle?

[1948man]

Congratulations on getting an "L" model Navuud. It's the flagship model of the GS fleet. Seems odd that only one cylinder would be firing out of 4. The experts will be along soon to set you on the right path.

[chuckycheese]

Nahhhhhhhh!

GS motorcycles won't run with only 1 out of 4 working.

[GabrielGoes]

Just out of curiosity, JEEPRUSTY, have you ever owned a motorcycle?

that is the funniest thing i have ever seen that should be my sig

[koolaid_kid]

I had to laugh also. My T200 had the first vacuum petcock I ever saw, and all street Suzukis I owned since then had a vacuum petcock.

[JEEPRUSTY]

Just out of curiosity, JEEPRUSTY, have you ever owned a motorcycle?

No but I own a book on etiquette care to borrow it.

For some reason I thought this was a twin cyl. bike.

[koolaid_kid]

Darn. I was hoping you would say that you stayed at a Holiday Inn Express.
I'm just teasing, don't take it the wrong way.

[navuud]

!!!!!!!!!

Thank you guys for the replies, except the tangent that took place in the last 4 posts... =P

I was listening to the engine while it was running and noticed that it was burping on one of the other exhaust pipes trying to fire, so I went out and bought 4 new spark plugs... again... and voila the bike is running beautifully, it almost scared me the amount of power coming out of it, intimidating, thought for a second I would need to put my hair into the bike like Avatar and bond with it before riding

I'm sure at this point the bike is cleaning itself out but I'm getting a good amount of blueish smoke, what would cause that?

Thank you guys again!

-Naveed

[JEEPRUSTY]

Thank you guys for the replies, except the tangent that took place in the last 4 posts... =P

I was listening to the engine while it was running and noticed that it was burping on one of the other exhaust pipes trying to fire, so I went out and bought 4 new spark plugs... again... and voila the bike is running beautifully, it almost scared me the amount of power coming out of it, intimidating, thought for a second I would need to put my hair into the bike like Avatar and bond with it before riding

I'm sure at this point the bike is cleaning itself out but I'm getting a good amount of blueish smoke, what would cause that?

Thank you guys again!

-Naveed

residue of fuel in the pipes could cause smoking.
maybe your rings need to settle back in.

Fresh gas an a good long drive are n order.
the smake should settle down after a while.

[BassCliff]

Greetings and Salutations!!

Hi Mr. navuud,

Hopefully you will re-visit your thread and pick up your "mega-welcome". It's good stuff. Let's get started.

Anyway, I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[BassCliff]

For some reason I thought this was a twin cyl. bike.

Hi,

All of these classic GS bikes from 550cc on up have inline 4 cylinder engines.


Thank you for your indulgence,

BassCliff

[Texasgs]

Hi guys, I should say that I am new to the site ergo hello everyone!

About a month ago I purchased a 1981 GS650 from a friend of mine for $400, his only words to me were - "it won't start, and I'm leaving town, take it"

This is my first bike and my mechanical skills are mediocre at best, but heres what I've done.

After hauling the bike over to my backyard I hooked it up to a battery charger, a day later and we've got power! I tried starting it and nothing happened, checked the spark plugs and compression - the spark plugs needed replacing so I did that, and the compression was between 140-160 (according to the manual that's ideal).

After this I was able to start it, however with some trouble so I took out and cleaned the carbs, and now i've got it running, HOWEVER only one of the exhaust pipes is getting hot, I suppose that tells me that its only firing out of one cylinder. Am I looking at sticky valves? Coils? any suggestions would be greatly appreciated.


Edit: When you're sitting on the bike, the second exhaust pipe closest to the engine is the one that is heating up.

You can eliminate the valves, if there were any problems there it would have shown up in the compression test. Pull the plugs out of the cylinders that are not hitting, and see if they are firing. If they are firing it is pretty safe to assume the problem is the carbs.