Gs550l carb issue

[gs550l]

Hi,
I am new to this forum and I am looking for some advice/direction. I recently purchased a 1982 GS550L with 9,000mi on it and I am in the process of getting it running. It only ran on1 and 2 cylinders when i first got it but now after taking the carbs off and cleaning them 1 2 and 4 are running smooth. The number three pipe does not get hot even at high RPMs. I have had the carbs apart twice and thoroughly cleaned them. Every jet and passageway looked good. No fuel is getting in the cylinder plug is not gas fouled and exhaust is free of blockage. Compression is 20psi low on #3 I think it was 150 or something but I did not block off vacuum when I checked it. Bike had a fuel filter on it and tank is clean as can be inside. Any ideas? I am at a loss on what to do next.

[tom203]

Sitting on bike, we call extreme left cylinder #1 (under clutch hand). So does this mean your cold cylinder is #2- petcock vacuum line attaced to #2 carb? If yes, then you might have a bad (leaky) petcock. You can plug vac port at carb, use "PR" spot on petcock and see if stuff changes. But don't forget to switch petcock to "ON" when bike ain't running

[gs550l]

carb

2 carbs 4 ports the vacuum line goes from the 3 port over from left(clutch) side. I will try blocking it off and see if anything changes
thanks

[Steve]

If you have two carbs, you don't have an '82 550.

The siamesed carbs started with the '83 model.

Maybe your bike was made in '82 for the '83 model production run?
Bikes made after July or August of '82 were '83 models.

.

[gs550l]

number three and four share the same carb for the float so I know there is fuel getting to the bowl. the passageways and main jet are clean and number three cyclinder still does not get hot. I checked valve clearance and there all good. any ideas? I wrote that I checked the exhaust for blockage but I just took header pipe off and nothing there at the cyclinder.

[gs550l]

If you have two carbs, you don't have an '82 550.

The siamesed carbs started with the '83 model.

Maybe your bike was made in '82 for the '83 model production run?
Bikes made after July or August of '82 were '83 models.

.

Yes it has two carbs

[Steve]

With only two carbs, it has to be '83 or newer.

Here is an '82 550L:



Here is an '83 550L


You should see several differences, like the front axle placement, front tire size, cam end covers, finning on the cylinder head, side covers, air box covers, rear shocks, rear footpeg/muffler mounts, seat shape and probably a few other things as well.

Which one of these more-closely resembles YOUR bike?

.

[gs550l]

Bottom picture is my bike. Any solutions?

[Steve]

Bottom picture is my bike.

Then that would be an '83 bike. Note that production for the '83 models started as early as August of '82, so the production date on the VIN plate might show an '82. Look in the lower right corner of the VIN plate to see if there is a letter at the end of the VIN. If it is "Z", it's an '82. If the letter is "D", it's an '83.

Any solutions?

Not yet, but I do have a couple of questions, based on your original statement.

I have had the carbs apart twice and thoroughly cleaned them. Every jet and passageway looked good.

How did you "thoroughly clean them"? And how did you inspect the passageways to see that they "looked good"?

You can NOT simply drop the float bowls and spritz around some carb cleaner. You need to thoroughly DISASSEMBLE the carbs, dip them for 24 hours in Berryman's (or Gunk) Carb Cleaner Dip, rinse them thoroughly with HOT water, spray a little carb spray through the passages, then flush them out with compressed air, then re-assemble them, using new o-rings from cycleorings.com. The passages that have the greatest impact on the way the bike will start and idle can NOT be inspected visually. Neither can they be cleaned with a simple burst of carb cleaner spray.

We also have not seen verification on your cylinder numbering. Cylinder one is on the LEFT, under your clutch hand, cylinder four is on the RIGHT, under your throttle hand.

.