Running on 3 ?

[Par6]

Hi everybody, new excited owner here but with a few problems
The previous owne said the bike had been laid up for a couple of years and wouldn't start, well I fitted a new battery fresh fuel and after a few attempts she fired up, sorry she's a 1981 gs550e, but only runs on 3 cylinders ? The right downpipe is stone cold, only getting slighty
Warm after the bike has been running a couple of minutes.?
I removed the carbs and removed the pilot jet and main jet, cleaned them, although didn't appear blocked, refitted everything but still nothing on that cylinder ?
Any help much appreciated cheers, Wayne.

[bonkas]

Try swapping the plug with another cylinder, see if the problem follows the plug.

[Par6]

Fitted brand new plugs and there's a healthy blue spark on the non firing cylinder, the plug is bone dry.

[Steve]

..., but only runs on 3 cylinders ? The right downpipe is stone cold, only getting slighty Warm after the bike has been running a couple of minutes.?
I removed the carbs and removed the pilot jet and main jet, cleaned them, although didn't appear blocked, refitted everything but still nothing on that cylinder ?

Newbie Mistakes 1a and 1b.

1A) (NEW) Trying to diagnose running problems on a bike with an unknown maintenance history is an exercise in futility until a baseline is established though proper maintenance. Things like clean carbs, properly adjusted valves, sealed intake system (airbox, carb boots), a clean gas tank (no rust), and a properly functioning petcock are 100% mandatory for the bike to run properly. It's best to perform all the bikes maintenance when you first get the bike, and then if problems show up you will know what the problem is not.

1B) Incomplete carb cleaning. A proper carb cleaning requires a full tear down, soaking the parts in carb dip, and reassembly with fresh O-rings (cycleorings.com). Pilot jets, choke tubes, and pilot circuit passages in particular need a proper cleaning before the bike will run right. Even if the bike seems to run right, if the O-rings are original they are sure to be hard and brittle thus problems could be right around the corner. This is a link to a carb tutorial that you may find useful... LINK

2) Not replacing the intake boot O-rings. The classic "hanging idle" is often traced to this simple fix since air gets sucked past the old O-rings and into the engine causing a lean condition. Most GS bikes have these O-ring, but not the 2nd generation 750 or 1100E family. While you are at it, make sure the entire airbox system is 100% sealed, since drawing false air into the system will increase running temperatures and make the bike run poorly.

3) Not adjusting the valves. The valves tighten with mileage, and once all the clearance is gone the valves hang open which not only results in poor running but damages them as well - burns them. If you wait for your bike to misbehave before performing this critical maintenance, you may damage the engine.

4) Trying to run the bike without the airbox...or installing pods, or a header, w/o rejetting. The air/fuel ratio will be drastically lean, which will not only cause running problems, but likely damage the engine too by causing it to run hot. Installing a free flowing exhaust will likewise change the jetting requirements, but not as drastically as pods.

5) Ordering "carb kits" full of inferior aftermarket jets. A new O-ring kit from cycleorings.com is all that's necessary most of the time. Get some new float bowl gaskets and pilot jet plugs if necessary from a place like Z1 Enterprises to supplement the O-ring kit.

6) Trying to clean out the brake system full of brown gunky fluid by flushing the system. If the fluid is dark and brown the only way to clean the system is a full tear down and clean out otherwise chunks will remain behind in the system. While your at it the old rubber brake lines should be changed. Suzuki call for replacing the lines every 2 years, so if your bike still has the originals you are 28 years overdue. The old lines will lead to spongy brake lever feel and contaminate the fresh fluid you just installed.

7) Waiting for the charging system to fail, instead of cleaning up the old wiring. Many a battery have been boiled dry after the grounds corrode. Running a dedicated ground to the battery, or a solid frame attachment point, is strongly advised. Suzuki also botched the stator wiring by routing one leg up to the now discontinued head lamp switch. This needless wire path often overheats and damages the harness in the process. Do yourself a favor and rewire your charging system: run the stator wires directly into the R/R, make sure your R/R has a solid battery or frame ground point, and run the positive (power) R/R output either straight to the battery (with 20A fuse in-line) or though the regular fuse block after you check for resistance in the circuit and repair as needed.

8) Using the wrong oil and/or gasoline. Auto oils have less zinc and phosphorus (high pressure additives) than they used to since the EPA has mandated reductions to protect catalytic converters. Motorcycle oils are fine but expensive, and even motorcycle oil has reduced additives these days. Diesel engine oil is cheap and contains lots of high pressure additives appropriate for our engines. Shell Rotella oil is even certified for use with wet clutches if that makes you more comfortable, although just about any diesel oil is fine. As for fuel, Suzuki calls for use of Regular gas. Using Premium provides no positive benefits for your bike and is more expensive.

9) Search out the information about your upcoming wrenching tasks before going off unprepared and possibly damaging something. Search using "Advanced Search" and then click "Titles Only" to quickly hone in on the topic at hand. Almost every possible question a newbie could ask have already been answered. For example: there are tons of threads on how to avoid broken exhaust bolts and float posts. Sadly, most newbies learn these tricks AFTER they damage their bike.

10) Buying a 30 year old motorcycle because it was cheap without any mechanical knowledge and no interest in learning. Paying a shop to work on your 30 year old motorcycle is not advised unless you have lots of money to spend and know for a fact that they are trustworthy.

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[sedelen]

Fitted brand new plugs and there's a healthy blue spark on the non firing cylinder, the plug is bone dry.

If your getting a healthy blue spark on the non firing cylinder, with the plug being bone dry, you're not getting any gas.
Have you ridden it? Does it continue to run on 3 cylinders after awhile?
Or does it do this at start up? If it does this on start up and runs normally after awhile it could be your choke circuit is plugged up.

[Par6]

Not ridden it, not legal yet. The bike runs on three with the choke on, any attempt to use the throttle and it dies, choke in and it dies?

[Steve]

Not ridden it, not legal yet. The bike runs on three with the choke on, any attempt to use the throttle and it dies, choke in and it dies?

Did you see my earlier post?

Did you understand it?

Here it is, with no misunderstanding:

CLEAN THE CARBS.

It is quite obvious from your post that the passages inside carb #4 are plugged, not allowing gas to flow through them. It is not good enough to pull the jets to make sure they are clean, you need to clean the passages that feed the jets. The only proper way to do that is with a full tear-down and soak, OVERNIGHT, in Berryman's or GUNK carb cleaner dip, then re-assemble them with new o-rings from cycleorings.com.

Gee, that sounds a LOT like Newbie Mistake 1B, doesn't it?

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[Par6]

Thanks for all your help and advice. The carb cleaning stuff you mention aren't available over here, I'm in the UK, I'll try and source an alternative, would ultrasonic cleaning be useful or just stick to the chemical stuff ?

[sedelen]

Not ridden it, not legal yet. The bike runs on three with the choke on, any attempt to use the throttle and it dies, choke in and it dies?

I have lost a cylinder once or twice and with only a noticeable loss of power and not as smooth running, however it did run otherwise without choke and accepted throttle once warmed up.
Sounds like you got plug up carbs or massive air leaks or both.

[Par6]

The float bowl on the non running cylinder is full of fuel so there is fuel getting there just not getting from the bowl to the cylinder head.
As far as having air leaks, when I removed the carbs I didnt see any o rings on the intake rubbers, I've heard these mentioned, where do they fit ?

[rustybronco]

Is your bike an 8 valve or a 16 valve model as I can't seem to find a 1981 GS550E in the parts diagrams over here?

[tkent02]

Ultrasonic cleaning is fine, do you have the equipment for this or would you be paying some shyster to do it?

[Agemax]

Thanks for all your help and advice. The carb cleaning stuff you mention aren't available over here, I'm in the UK, I'll try and source an alternative, would ultrasonic cleaning be useful or just stick to the chemical stuff ?

you can get GUNK in the UK, Halfrauds or most car accessory shops sell it. U/S cleaner is good but soak them in carb cleaner first then zap em in the U/S cleaner.

[sedelen]

Is your bike an 8 valve or a 16 valve model as I can't seem to find a 1981 GS550E in the parts diagrams over here?

There is no '81 GS550E for parts at Boulevard Suzuki.
However there is a '80 GS550E, and yes there be "O" rings in the fiche, item 23 in the parts fiche.

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=93002&category=Motorcycles&make=SUZUKI&year=1980&fveh=2107

Could be a '81 GS550T,
and there be "O" rings in those boots, item 23 in this fiche.

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=93524&category=Motorcycles&make=SUZUKI&year=1981&fveh=2116

Or it could be a '81 GS550L, and yes there be "O" rings in those boots also. Item 22 in this fiche.

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=93299&category=Motorcycles&make=SUZUKI&year=1981&fveh=2112

No, carb boot "O" rings equals "massive air leak!"

[Steve]

The carb cleaning stuff you mention aren't available over here, I'm in the UK, ...

This is new information, and rather important. In fact, it is so important, would you mind taking a few moments and updating your profile to show your location?
As you can see, it really does matter where you are on this little blue marble we call "home".

Oh, while you are updating your location, why not generate a simple signature that tells what bike you have and are working on?
That way, you don't have to remember to mention it every time you ask questions.

..., would ultrasonic cleaning be useful or just stick to the chemical stuff ?

Ultrasonic cleaning can work, Agemax gave some tips on that.

The float bowl on the non running cylinder is full of fuel so there is fuel getting there just not getting from the bowl to the cylinder head.

Fuel has to get through some passages inside the carbs and through the jets before it makes it to the cylinder head.
Dollars to donuts (Pounds to biscuits?), those passages are plugged, not allowing fuel through.
A thorough cleaning will take care of that.
Agemax is also in the UK, so can give tips on where to source the proper chemicals and tools.

As far as having air leaks, when I removed the carbs I didnt see any o rings on the intake rubbers, I've heard these mentioned, where do they fit ?

You mention "intake rubbers" as if this is a 16-valve engine. Since we did not have that model here in that year, you will have to provide some more information.
Pictures would do very nicely. Before you figure out the picture "thing", though, what do your cam end covers look like?
Are they round and shiny or are they more rectangular and not quite so shiny?

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