Question about 1980 Suzuki Gs 550 L

2 Answers

1980 Suzuki GS550 with problems

I just bought a 1980 suzuki GS550E and already running into problems.

First it doesnt want to start up on its own but when it does it runs fine.

Second two of the cylinders seem to be running lean. Hooked up my meter and two were running at the 350 degrees F and the other two were about 90-100 degrees. Do they just have to be adjusted? If so do i set the vacuum on the carbs and what would the spec usually be?

Third the battery seems to lose its charge alot. I hooked up a DVOM the the battery while it was running and it was reading 11.75 volts. Is this a normal reading or does the charging system seem like its not working?

If anyone can help, it is greatly appreciated. Im just trying to get this bike in the road soon.

Posted by on

  • 2 more comments 
  • elementfreak May 24, 2009


    If your sitting on the motorcycle the two cylinders would be #1 and 3 from left to right.

  • elementfreak May 24, 2009

    Mr BrokRench,

    With the battery voltage i will charge it to 12.6 volts, figured it would be the same as a car battery, and then start the bike, if it wants to. When i hook up my voltmeter the volt stays at a constant 11.75 volts even when you rev it up past 3000 rpms. The guy who i bought the bike from also coverted it to a single pipe and took out the baffles. Would that call for re jetting the carbs?

  • elementfreak May 30, 2009

    Alright. I figured it was probably a good idea to get a new battery and spark plugs considering thats what some of the advise was. I also drained the gas in the tank and added fresh gas with the seafoam in it.

    Now got a couple more problems developing. As i go down the road the bike wont rev past 2500 rpms. Also restricting the air flow to the carbs actually speeds up the engine. This sounds like its running lean right?

  • Dick
    Dick May 11, 2010

    The fact that you have two cylinders in the 90-100 degree range tells me those two are not firing. Could be ignition, I think there are two coils on the bike. Which two are running cool?



2 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    An expert that has over 500 points.


    An expert who has answered 200 questions.

  • Expert
  • 212 Answers

First thing I would do is change the battery and spark plugs. start there.

Posted on May 24, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Master
  • 1,623 Answers

Hello elementfreak...First thing you need to do is run a compression check on all cylinders...readings should be within 10-15 psi max of each other. Next, check for vacuum leaks, a cracked hose, faulty carb boot, or any slight leak will cause a lean condition and hard starting...The choke and pilot circuits share passageways. When pilot jets become obstructed, the choke circuit compensates and allows engine to start and idle with choke, but stalls without choke. If the bike has had the same gas in it for over 6 weeks, "varnish" is possible in the system...Purchase a can of "Seafoam" at your local parts store, pour 1/2 of in a full tank of gas, and the other 1/2 in 2nd tank of gas, after you use the 2nd treated tank of fuel...replace fuel filter.
This stuff works better than anything the dealers sale.
A carb sync tool for mutiple cylinders engines will be needed to sync carbs, this is done after all other problems are corrected. If your bikes exhaust or air intake system has been modified from stock...The air-fuel mixtures will need to adjusted by selecting the correct jetting (carbs need jetted).
Tuning is not easy and often requires a wide selection of air, main, and pilot jets, jet needles and needle jets.
11.75 volts is not a fullly charged battery, 12.2 to 12.6 volts is.
A low voltage battery will create hard starting, and poor spark. Faulty ground cable terminals are common, check the main ground at frame. Trickle charge the battery over night to a full charge and test, replace if needed. The stator/rectifer systems on these older bikes won't indicate enough amperage return untill the engine RPM is 3000 and above..Check the connectors for corrision....
Hope this helps and gives you a place to start...Good Luck
Ride safe and ride smart...

Posted on May 24, 2009

  • Mr BrokRench
    Mr BrokRench May 25, 2009

    Yes..the 4 into one exhaust without baffles will have a lot less back pressure than the stock exhaust...Most aftermarket exhaust system mfrs will recommend a carb jet change to prevent lean fuel mixtures. Are you sure the carbs are the stock ones? The bowl should be on the sides, if they are. Also check the plug wires with an ohm meter for internal core damage...Your GS is 30 yrs old

    With the tank removed you can see all the places for a potenial vacuum leak...note the carb mount boots lines & hoses.
    In this pic you can see where lines have been pinched off and not allowing enough fuel to flow. Also check the fuel pitcock, it's a vacuum type and tend to stick after yrs of service.
    These are just a few places to inspect.

    Here is a two tests you can perform after every repair or change you make to check for improvement. (BOTH low and high throttle tests are important for precise tunning)

    Low throttle: Run around the neighborhood at low throttle first, not
    getting above 3000 RPM. Shut it off and check EACH plug. Those plugs that are clean, tan, or medium brown are correct mixture. If the plugs
    are black and sooty, then you know those cylinders are too rich. You may
    be able to adjust the idle mixture with the pilot screws, but probably
    not. Go test it again. If that doesn't work, you will need to remove and
    re-clean the pilot circuits and choke/enrichment valve. Sorry, that's the
    only way to do this.
    High Throttle: Run out on the highway at 1/2 throttle or better for about
    5 minutes or more. This will likely put you into the 80MPH range, so pick
    your test track carefully. After running along for the 5 or more minutes, hit the kill switch, pull in the clutch, and pull over on the shoulder.
    You cannot slow down with the engine running, or you won't get correct results. Check each plug again and record your results. Chances are the plugs are okay, especially if it ran okay. Same reading method applies.
    If any are sooty, then you will need to re-clean the main circuits in that carb and recheck the float level.
    Backfiring, spitting and coughing typically indicate one or more cylinders are too lean. This is the same kind of behavior you get when you push the choke off too soon (and for the same reasons). In fact, you can sort of troubleshoot lean mixtures by adding a little choke to see if that improves the running. If it does, you're too lean.
    If one or two cylinders are off and the others are okay, according to the plug readings, it will seem like the whole engine is running poorly. I've had that experience myself. Unfortunately, there are no shortcuts.You will have to read the plugs, re-clean troubleshoot, re-check everything, and re-test until you nail it.
    Good Luck ...i hope this information will help get the old GS puuring like a kitten again.



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I have a 1980 Suzuki. GS550E and it only really wants to fire when I'm letting go of the starter button what is making it do that ? And also what's the fuel ratio?

Charge your battery up and try again. The starter is draining too many amps and not leaving enough for the ignition circuit. The battery may be failing or have a bad cell. 5 years life max.

Feb 01, 2016 | Motorcycles

1 Answer

When it gets hot will barelly turn over and will not start if i let sit and cool it will start and run fine what could the problem be pls some one help

Hi Henry, I'm leaning towards weak battery or starter, do a proper load test on the battery and the starter circuit, for more information about your question please visit the website below. Good luck and have a nice day.
1980 Suzuki Motorcycle Service Repair Workshop Manuals

Sep 26, 2015 | 1980 Suzuki GS 750 L

2 Answers

What is preventing my 1980 Suzuki gs550l from starting?

Sounds like a loose connection or poor ground clean terminals with sand paper Also make sure that the battery terminals are not broken or cracked

Jul 17, 2014 | 1980 Suzuki Gs 550 L

1 Answer

I bought a 1983 GS550E and the cam chain rattles a bit.Is there any adjustement possibility or do I have to change the chain?

Something you can try....

In the above illustration, item #10 is listed as "Chain Tension Adjuster".

You can try adjusting this to see if it helps.

Mar 06, 2014 | Suzuki Motorcycles

1 Answer

Still workin on my 1980 suzuki GS550 L. Inline 4 cylinder. My Problem is When I run the bike I have gas coming out of my overflow tube for the number 1 and number 2 carburetors but if I disconnect the...

Hi, Davescheier6 and the usual suspects are:
1. Damaged or restricted fuel tank venting system.
2. Loose float bowl screws.
3. Damaged float bowl o-ring.
4. improper fuel level in the float bowl.
5. Worn or dirty inlet valve or seat.
6. Damaged or leaking float assembly.
7. Particle contamination in inlet fitting cavity.
For more information about your issue and valuable "FREE" downloads that you will need please click on the blue links below. Good luck and have a wonderful day.
Carbs leaking fuel from air filter
Carbs leaking Here is how to fix it
Suzuki GS550 Service Manual
OEM parts for Suzuki
Suzuki GS500 Owner Manual

Apr 23, 2017 | 1980 Suzuki Gs 550 L

1 Answer

Wiring for 78 suzuki gs550e stator ant regulator and rectifier

The site below (exploded views - part chart) should get you mobile again, see electrical and wiring harness sections . The rest of the bike is there also. Cheers.

May 20, 2010 | 1980 Suzuki Gs 550 L

2 Answers

In have a 1985 suzi gs550e it starts but only

Sounds like a fuel supply prob....have you opened the choke to see if will run ??

When you say "cleaned carbs" did you mean removed / stripped / refitted?? If not do so.

May 13, 2010 | 1983 Suzuki Gs 550 L

1 Answer

I have a Suzuki Vitara 2002.. it'll start and run but then turns off here and there... when it turns off, I try turning it back on but won't start.. it'll only start when I try starting it again about 15...

Write suzuki directly, or contact them,first try your local suzuki dealer , if that doesnt work try corporate offices. This is a very common problem that occurs alot in most suzuki's. I myself just bought a 2001 vitara 2 weeks ago & have the same problem. It starts up fine in the morning but if I stop somewhere with the car & let it idle , it starts to stall & shut off completely & then I have to wait 10 to 20 minutes before it will turn on. Suzuki should admit to this problem & have a recall. I have read hundreds of articles of people all over the states with the same problem. The dealers are telling everyone " well we dont know what the problem is". Its their JOB! They should know!

Nov 27, 2009 | 2002 Suzuki Vitara

1 Answer

Leaks gas

the needle and seat in the carb isn't seating. First, shut off the petcock, and drain the fuel bowls with the screw on the bottom of the bowls. Let all the gas drain out of the bowls.Tap lightly on the carb with a small hammer, the refill the carbs, see if it still leaks. if it does, you need to pull the bowls off, remove the float and clean out the needle and seat, and put it back together

Jun 10, 2009 | 1980 Suzuki Gs 550 L

1 Answer

What is the reliability of the 1980 suzuki gs750l, .

Many of these bikes will run fine with high miles. I would check the tires, fork seals for leaking fluid. Listen to the engine and exhaust for odd noises. Pinging and rattling are bad. See how it shifts. These bikes require a special tool to replace the clutch plates and that can be expensive.

I owned a 1982 GS550L with 33k Miles on it, and it rode fine. Watch that tire pressure and suspension. Other than that, enjoy your bike!

Mar 30, 2009 | 1980 Suzuki GS 750 L

Not finding what you are looking for?
1980 Suzuki Gs 550 L Logo

5,071 people viewed this question

Ask a Question

Usually answered in minutes!

Top Suzuki Experts


Level 3 Expert

76846 Answers

Arnie Burke
Arnie Burke

Level 3 Expert

4536 Answers


Level 2 Expert

83 Answers

Are you a Suzuki Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides