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**Anonymous** · 01-24-2005, 11:49 PM

Pilot jets are clogged.

They never get better with any type of gasoline additive.

Mine got progressively worse to about the same point as yours has. I had to take the carbs off and cleaned them twice. Missed the culprits, pilot jets the first time, and that was what was all the trouble.

Someone else on the Forum said he replaced the pilot jets everytime he took the carbs apart on the 550s that use the little pilot jets. That's a little obsessive in my mind. I used Berryman's Chemtool B12 carb additive (straight strength) to clean all carb parts. It works. There's no comparison to spray can carb cleaner.

Anyway, the jets you'd suspect are the main jets which are pretty big and obvious. They probably need a cleaning too but that's not the only problem.

I used ONE strand from a picture frame hanging kit wire. Heated the end of the strand of wire with a cigarette lighter and shoved it into a toothbrush handle (not the bristle end) to use as a cleaning tool.

Between repeated soakings in the Chemtool B12 and running the wire through, I got all the jets perfectly clean. I cleaned everything else too while I was in there. Those jets sure were CLOGGED.

Runs great now.

About the only parts breakdown to use to find (generally) where parts go is from the BikeBandit.com website or Crotchrocket.com or AlphaSports.com. AlphaSports.com is easiest to get around in since their layout is sort of like Windows Explorer. Crotchrocket seems to have more parts for our GS550Ls and much better prices than all others although I don't know about shipping and handling charges yet.

Good luck.

Dipping the carbs won't clear the pilot jets. I never dip carbs (car, motorcycle, or other) unless I have some reason to believe an internal port is clogged and I can't get it out with other solvents and an air compressor..

**AOD** · 01-25-2005, 01:12 PM

Carb cleaner spray has always worked for me, even with the pilot jets. Remove the carbs, take the bowls off, remove the float and pintle, and the jets and spray everything out. Soak the jets if you need to and spray all the passages of the carb bodies.

This fixed the same problems I had when I got a bike that sat a bit.

~Adam

**Anonymous** · 01-25-2005, 04:08 PM

Everyone seems to say it's the pilot jets. What's the reason for this? Why not somthing like the spark plugs having a bad gap? (another forum directed me toward those) Something to do with it starting with ether?

**Anonymous** · 01-25-2005, 05:15 PM

OK, Adam had good luck with spray can carb cleaner.

It didn't work for mine mostly because my pilot jets were 100% completely clogged with HARD green stuff! Again, I had to repeatedly soak and run the little wire through to get them clean.

My GS550L sat for more years than it was ridden. A 1985 model with less than 4000 miles on it when I got it in June 2004. It was stored covered inside a garage for 17 years. That should give us all an idea of how long gas sat in the carbs. The guy I bought it from said the carbs had been cleaned and the bike had been recently serviced. Whoever might have done the carbs didn't do the pilot jets nor did they do the main jets because they were clogged (but not quite as bad) as well. Of course, it might have been a year or 2 since the carbs had been done because he had gotten it from his sister-in-law 2 years before.

*
Anyway, I forgot to state at the beginning of yesterday's answer how I determined my problem for hard starting: hard starting at first. Poor acceleration in low to mid speeds. Harder starting (10 minute cool down in summer, and had to use 100% choke to start again). Days later I could only keep it running while riding with the choke on, then one day at work a no-start with a fully charged battery. After the bike sat for half hour because I'd run the battery down (when I finally got a jump start), it fired right up after sitting for half hour. Then days later went to no-start at all:

Assuming the engine is in fair mechanical condition internally,
The question is spark or gas present or not?

Crank the engine.

Pull all the plugs.

Are the plugs real wet with gas? If so, you're getting enough gas.

I WASN'T. Mine were nearly dry after several minutes of on/off cranking. That's when I went to troubleshooting fuel delivery. Gas in fuel bowls. Yes. WET gas on plugs. NO. Must be carbs. (If you didn't have gas in fuel bowls, could be petcock, fuel filter (if you have one), or maybe floats/needle and seat inside one or both of carbs.)

Put the high tension lead onto each plug and ground the plug threaded part by letting it touch metal.

crank engine.

If you get blue sparks, then ignition ok.

Some bikes are said to not start or run without their air filter. I never tried running with mine off so that was not an issue. I did check for clogged air filter but I put it right back afterwards. You can bet the plugs would be wet without an air filter/cleaner.

I'll never forget this little troubleshooting exercise. This troubleshooting stuff can be done in a parking lot if you're out stuck somewhere. ("Been there, done that"). Where you go from here in troubleshooting is subject to more debate but I hope you get the idea.

Whether you want to clean carbs in the parking lot is another judgement call. I was able to get my bike home.

Again, good luck and I hope I clarified somethings.

P.S. Again, a good gasoline stabilizer will prevent lots of these problems. Too much stabilizer in gas smells funny and the engine runs crappy but your carbs won't clog. It's a tradeoff that I don't have an exact formula for yet.

P.P.S. Everyone mentions did you check the spark plugs? For 4 stroke engines I'm almost entirely convinced that if you get a spark across a plug it's good enough to start the engine. How well it will run after it's going is another issue. The gap and how dirty the insulator are affects the intensity of the spark and cooling of the plug so it doesn't self-destruct. That's why we regap plugs after we clean them if we reuse them, becaue the gap became wider and it's harder to get a hot enough spark across the electrodes. 2 stroke engines (weedeater, for one) are critical about spark plugs. I've had them look good. Spark decent and not run in an engine. A little Dawn dish detergent and a good rinse in water cleans the 2 stroke oil off the plug and it goes back in and starts the first time (most times). That 2 stroke oil must short out the plugs.

Seriously, this will start another debate but I've found this about spark plugs consistently true on many cars, trucks, and lawn equipment. My 4 stroke tiller burns oil like there's no tomorrow and it shorts out the plug but you can see the whisker between the center electrode and the ground electrode. I clean it, put it in and tiller runs again, billowing out smoke as normal for worn rings. (I till 25 feet a year, 1 time if I'm a lucky, who cares about a little smoke?)

Spark plugs don't cause a no-start for 4 stroke engines unless the're physically damaged (broken insulator or bent ground electrode). (Again, "been there, done both"). I'm going to get hammered on that statement but I believe it.

Lastly, if you know the bike ran recently but it has just gotten worse really, really fast, we all waste our time doing compression and/or leakdown tests too soon. These tests come on a no-start or bad runner that we don't know the history of or as a next step after the above steps are completed and it still won't run. I did compression test ONCE, cold (couldn't get it running, remember). Nice information for future troubleshooting but useless in getting it running. If I had just read the plugs (lack of gas was an obvious FACT), I could have jumped straight to the carbs. (And I could have waited for a while longer before I bought new spark plugs too, they looked GREAT). NOW I KNOW.

Those plugs should be WET with gas. We're talking old-fashioned carbs here not EFI. They don't shut off with a computer like cars do.

Regarding the last post, starting with Ether is another issue. I wish I knew the answer. I have a lawnmower that I must use Ether consistently to start when cold (Briggs and Stratton engine). Every time. I always assumed I can't get enough tug on the pull cord because it's a belt/drive disk Snapper mower and there is always a serious load even when disengaged. Runs great after starting.

The motorcycle issues here are about DECLINING, DETERORIATING, getting WORSE starting and running on a particular model GS 550 L 1983-1986 that has a unique carburator that uses tiny (too small) pilot jets compared to other carbs (according to some other posts). There are other unique features like each carb is sort of a 2 barrel in design but the OUTLETs feed directly into each cylinder not split like a car. The fuel delivery is common using one float per carb. So we can read the plugs and see if float is stuck closed, a pair 1&2 or 3&4 have no gas, then we know exactly which one is messed up and why. The jets, and pilot jets (and airflow) except for the common diaphram are independent of each other and can be in various states of misadjustment or clogged in our case.

Sorry to go off-topic about lawnmowers but this is just my experience and opinion.

Time to get off the "soap box" too.

**Anonymous** · 01-25-2005, 10:19 PM

Amazing response. Very detailed and usefull.

As I recall, the plugs were dry, but I'll go through those checks again just to make sure as soon as I can. Will update as soon as I get a free day.

Thanks again

**AOD** · 01-26-2005, 04:02 PM

What's the reason for this?

1. Pilot jets are very small and clog easily.
2. Fuel flows through the pilot jets on startup and lower speeds, which is why it's the first place to look.

~Adam

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