GS550L Won't run after carb work

[scott808]

Hi Guys,

I need your help. My bike was dying as if it was running out of gas. It would restart after sitting for some time, but it would die a few miles later. I pulled the carbs removed the easy stuff and soaked the jets. The only problem I found was on of the choke pistons was stuck. Thinking I was not getting fuel I replaced the needle valves and check fuel flow to the carb all the way to draining the bowls.

Sadly the bike would not start. After hours of trying I can get the bike to start on full choke if I don't give it any gas. It will run for a few minutes on full choke. If I touch the throttle it dies. If I move the chke setting it will die. Once it dies it will not start again until it sits for an hour or so. The idle setting does not seem to make any difference. 1983 gs550l with two mikuni carbs.

Please help. Thanks, Scott

[JEEPRUSTY]

Are you trying thisd with the airbox fully installed?

[scott808]

Air Box

Yes I tried without the air box think it should at least start but then remembered the air box issue. The air box is install. Thanks

[JEEPRUSTY]

Damnation!
SO my easy fix is gone.

Carb bowls are filling with fuel fine.........

[scott808]

Yes carb bowls are full. Looks like I wasted my money replacing the needle valves. No change. Thanks again.

[JEEPRUSTY]

hmmmm well introspection is what is needed.
That bike with clean carbs, air box installed, exhaust installed and with no leaks in the intake boots should start and run.

Did you disturb the idle adjustment needle valves?

I have also had a problem with the choke circuit in that the pick up tube was partly blocked.

As for the new parts just be thankful it is only two of each part.

[tom203]

You need to use "choke" in Hawaii?
Anyways, pulling jets and cleaning them is nice, but this doesn't ensure clean passages from pilot jets up thru and into carb throats- if they are gunked up, not enough fuel and engine will fall flat. Did this problem come on suddenly?

[scott808]

Prior to doing any work, the bike would suddenly die even at constant freeway speed like it was no getting gas. So I am thinking it is not something that would slowly degrade. The weird thing is the bike will start at full choke (which should not be required in Honolulu) and run for a few minutes, but like before I pulled the carbs, it needs to sit a while before it will start again.

[JEEPRUSTY]

Form what you describe it sounds as if it is doing what mine does when it runs out of gas.

When the bowls are starved of fuel it is often a real PITA to get them primed again. But as you say your bowls are full.

Regardless of anything else your experiencing a lean condition as evidenced by the effect of the choke on starting.

[scott808]

I pulled the carbs again and disassembled. Main jets needed cleaning but no smoking gun. I installed the carbs and airbox. No changed whatsoever. I get a little chug if the choke is on full, but the engine only cranks. The carb bowls are full and not sign of flooding. Any suggestions? I gotta ride this weekend! Thanks

[OldVet66]

Sounds like a collapsing or kinked fuel line.

[JEEPRUSTY]

maybe try running it on prime in order to bypass the vacuum hose and diaphraghm as a source of the problems.

[chuck hahn]

How much fuel is actually in the tank? Its got to have about 1 gallon in it to NOT have to be set to REServe. Do the PRIme and leave it there trick like Jeepster said. If it stays running, quickly shift over to REServe and see if it stays running. If so, get it filled up.

[scott808]

Before I did any work on it, it always seemed to run better on a full tank. Once I burned over two gallons of gas it started acting like it was running out of gas. Filled it up and it ran great for another couple gallons. It seems to have gotten progressively worse. Or maybe just a coincidence. I can't seem to figure it out. The more I do the worse it gets.

[tom203]

You better remove petcock and see if the filter is gunked up. This would restrict fuel flow as tank level falls.