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Raw gas coming out of left tailpipe. Where do I begin?

870 Views 10 Replies 4 Participants Last post by  fnfalman
Getting my cycle back on the road soon. Cycle in question is a 1981 Suzuki GS450L parallel twin engine, 15K mi. Properly stored this past winter. Nothing funny, no mods, completely stock specs.

I went to start it up and there is raw (atomized) gas coming out of the left muffler (tailpipe). I thought maybe the carb was clogged and put a can of Sea Foam in the tank and took it for a 1-2 mile ride down the street. Nothing. No change. Still raw gas. Power sucks, as only one cylinder is doing the work.

Where do I start looking? Is is a spark plug issue? It doesn't have point ignition, it's electric. It almost seems like the left cylinder isn't firing, the right side seems to be firing fine, so the plug should be ok there as well. I replaced both plugs when I bought it last May so I don't think it is an age issue.

Any thoughts?
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sounds like intake valve hung open to me... or could be spark plug.. start there.. its cheap.. pull spark plug, turn over a couple time to "clean out" gas from cyl. install new plugs.. try it.. see how it goes. let us know
Does that bike have a vacuum operated fuel valve? If it does, then there is your problem. Let me know. It has absolutely nothing to do with the valves or spark plug. Don't ride it any more. If gas is coming out of the tail pipe, then the cases are filled with gas too. Open your oil fill cap and smell. 20 bucks says it smells like gas.
Sorry it took so long to check it out. I have my wedding coming up Saturday and me and the soon to be Mrs. have been running around doing stuff the last few days.

Anyways, I smelled the oil in the crankcase and it didn't really smell like gas. Scratched my head and thought Well, let's see what she does. Started up after a few tries (kinda cold today, like 42* for a HI). I let it warm up for a minute or two. Checked the pipes (one on each side) for raw gas and there doesn't seem to be any coming out anymore. I put my hand by the left pipe and cracked the throttle a few times and my hand was still dry.

There is a little that comes out of the right pipe at about 3/4 throttle, but might be just some smoke from the old gas and Sea Foam and stuff in the tank. I will take it out for a small spin tomorrow morning and see what happens.

If all is well, then what the heck was that all about? Just that vacuum thing got stuck? Something to be worried about? Money is kind of tight right now and don't know about spending more than $100 to fix a problem. It already needs a new front tire, a few light bulbs on the cluster, and maybe brakes (gotta check them). I have to dip into the wedding gift money for that stuff.
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Hmmm. Are you sure it is gas in the pipe and not condensation mixed with carbon build-up? I'm not saying your wrong, I'm just trying to help a fellow 10mm shooter out. If raw gas is coming out of the tail pipe, then it has to be getting into the cylinders. If it gets there, then it seeps past the rings and into the crankcase. If it does have a vacuum operated fuel valve (i.e. petcock- I hate that word), then there would be a line that goes into the intake boot or the very top of the carburator. Usually what happens on old bikes especially after sitting for some time, is the rubber diaphram cracks and lets gas run down the VACUUM line directly into the cylinders. If it got stuck then you wouldn't get any gas at all. Did you happen to leave the fuel valve on "prime" if it has one? There should be a fuel filter on the inside of the fuel tank. That would block any sediment, unless it has a hole in it. It's hard to diagnose a problem via internet.

CONGRATULATIONS ON THE WEDDING!!!!! Forget about the bike and concentrate on the honeymoon!!!!!:cheers:
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Seems like gas. I put my hand about two inches away from the pipe and it was wet, smelled like gas.

Yes, it has a petcock. Settings are PRIME, ON, and RESERVE. ON is the normal position for normal operation and storing and stuff. The only way gas goes into the cylinders in the ON setting is with the throttle open or ignition on.

I'll have to remove the fuel tank to change out some bulbs on the instrument panel. I will probably be replacing the fuel filet in the tank too. I would like to replace all brake lines and fuel lines, but I don't know about the budget yet.

It sucks trying to diagnose problems on the Net. My dad is checking with his wrench buddy at the firehouse in Oshkosh (WI) to see if he can help me out too. The guy is amazing with his know-how.

I almost want to take it in and have the bike shop go through it all and replace the brakes/ lines, fuel lines, and tune up the engine and balance carbs and stuff. Seems like a lot of work though. But I plan on riding a lot this year. We'll see.

Thanks for the congrats on the wedding. Got married this past Saturday (5-6-06). Was a blast. Best day of my life. Wouldn't trade it for the world. I didn't get any digital pics (forgot to bring our camera and have someone take pics with it), but I will scan some 4x6 prints of us and post a topic in GNG tomorrow. Doesn't feel any different. So far the only difference is a ring on my finger. She already is signing stuff with her new last name!

Got lots of gifts and about $4000 in cash. My wife said I can get my tire, brakes, and bulbs out of the money. The rest is going for credit cards and baby fund. Baby is due Oct 26, she is about 15 weeks along.

Might do a honeymoon later this summer. Stayed at the hotel in town at the bridal suite Saturday night and last night. It was complimentary because the company she works for owns the AmericInn in Calumet. Saved us $300.
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Ride all you could right now because once the bambino came...that's all she wrote.:supergrin:
Great , I'm glad ya had a good time!

Ok then, yes you do have a vacuum operated petcock. I would get a rebuild kit for the valve and for the carbs. Have the carbs and valve cleaned, rebuilt, carbs syncronized and adjusted, valve cleance checked, oil & filter changed, air filter checked/replaced and a fresh set of plugs thrown in to complete the tune up on the engine. To clean carbs properly they need to be COMPLETELY disassembled and every little hole needs to be checked to make sure it's free of debris. There is a lot of little, delicate parts in there.
Thanks. So a tune up is in order. Sounds good and thanks for your help.
Finally got it!!

Was lazy and finally got around to it last week. Went to start it up and nothing. Battery dead. So I charged it up; took a day and a half.

Yesterday I started up and all ran fine. Geared up and went down the road to get the rust off my riding skills. First time on a bike this year. Got about a half mile down the road and it died. Walked it back to my house. Not too shabby, I live in the country.

After a little cussing and swearing at running late for work because I figured it was bad fuel and spent 20 minutes draining the gas tank throught the fuel valve, my father in law took over so I could get to work. He filled it back up, changed the plugs. He got it to start, but it would backfire and then quit.

I got it to start this morning and had him take it for a ride, as the left tailpipe still had raw, vaporized gas coming out. After zipping back and forth for 10 minutes, we (he) figured out the problem.

The left carb was making the choke stay off for that cylinder and the left cylinder was running very, very rich. He sprayed some carb cleaner over the choke link and got it loosened up. Should work fine for now. He said the next rainy day he will help me take off the carbs and clean the choke assembly for me.

Went for a nice ride today before work. Not too far, just a little 25mi warm up. Tomorrow I am going up to Copper Harbor on the tip of the Keweenaw Penninsula. I will be running a blog on various small trips in the Keweenaw Penninsula on motorcycle.

Thanks for all your help guys. I love my bike so much I have decided to restore it and keep it. I had a self proclaimed Harley snob stop and check my bike out today. He gave me his info and said if I ever put it up for sale, give him a call. He said he would buy it in a heartbeat.

Call me weird, but the more I work on my bike, the more I get to know it and the more I like it. At first it was just a learner bike, but now it is a keeper for sure.
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I'm glad to see that the problem was inconsequential. Ride on!!!
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