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pyner101 · 03-28-2010, 01:43 PM

Hi, I have a 1981 gs550 which I have been rebuilding. I was given the carbs in bits so stripped them down, cleaned and put them back together. Now at the stage of starting it but having trouble. I have to put my hand over the carbs flooding them to get them to start. It takes a long time to get it going and there is a lot of smoke. These are the old type carbs, they have a screw underneath the carbs by the float bowl it is like the air mix screw. I can't find any reference about this screw and what adjustment it may need and if this is causing the problem. Can any one help me please?

A Star Ride · 03-28-2010, 02:39 PM

I'm no pro at carbs by any means, but that screw sounds like the drain.

mscuddy · 03-28-2010, 02:56 PM

It's the pump-jockey sockets, you have to use an oakum-packings on the float-spindles, but that's the easy part.

I don't know where you live, but there must be a motorcycle salvage yard close somewhere, right? Go there, quickly, and purchase a used rack of carbz for your poor Suzuki. Either that, or drive youself nuts trying to get those "carbs made from bits" to work worth a damn.

GO NOW! BEFORE IT'S TOO LATE!

speedtriplerider · 03-28-2010, 08:34 PM

i just sold my 81 gs 750 and it had the same carbs. the screws on the bottom are drain screws. there are so many thing that could be wrong if you dont know that much about carbs well good luck.

pyner101 · 03-29-2010, 12:29 AM

hi its not the drain screw, this screw tapers out to a sharp point and goes verticaly up into the card housing, these are slide carbs

seruzawa · 03-29-2010, 04:59 AM

Tapered screws usually means pilot screws. Try starting at 2 turns out from lightly seated.

MOKE1K · 03-29-2010, 05:42 AM

Seru is right, the fuel mixture screw's gererally start out at 2-21/2 turn out. Do you have the airbox hooked up to the bike that could cause a hard start. What about the bike, how longs it been sitting if at all, mileage, compression?

pplassm · 03-29-2010, 11:50 AM

Indeed. Without the airbox, you will be chasing jetting problems forever.

pyner101 · 03-29-2010, 01:45 PM

hi thanks for all your suggestions, i have some k&n filters for the carbs. there are pilot/mixture screws on the side of the carbs which can be adjusted when carbs are on, these pilot/mixture screws are underneath so you have to take the carbs off to adjust. i have never seen this on carbs before so am a bit confused with what they do (been working on bikes for 30 years) i will let you all know if i get it going.
thanks all for your help

MopedMarauder · 03-29-2010, 01:50 PM

Isn't the screw in the bottom with the float bowl the main jet? Maybe that's just for moped carbs.

03-28-2010, 01:43 PM	#1
pyner101 Registered Member Join Date: Mar 2010 Posts: 6	gs 550 carb problem Hi, I have a 1981 gs550 which I have been rebuilding. I was given the carbs in bits so stripped them down, cleaned and put them back together. Now at the stage of starting it but having trouble. I have to put my hand over the carbs flooding them to get them to start. It takes a long time to get it going and there is a lot of smoke. These are the old type carbs, they have a screw underneath the carbs by the float bowl it is like the air mix screw. I can't find any reference about this screw and what adjustment it may need and if this is causing the problem. Can any one help me please?

03-28-2010, 02:39 PM	#2
A Star Ride Registered Member Join Date: Oct 2009 Location: central Va Posts: 1,126	I'm no pro at carbs by any means, but that screw sounds like the drain. __________________ White Trash Hick from Appalachia

03-28-2010, 02:56 PM	#3
mscuddy MODERATOR X Join Date: Jun 2007 Location: Next to my still checkin the temp. Posts: 5,444	It's the pump-jockey sockets, you have to use an oakum-packings on the float-spindles, but that's the easy part. I don't know where you live, but there must be a motorcycle salvage yard close somewhere, right? Go there, quickly, and purchase a used rack of carbz for your poor Suzuki. Either that, or drive youself nuts trying to get those "carbs made from bits" to work worth a damn. GO NOW! BEFORE IT'S TOO LATE! __________________ A gun is a tool, Marian; no better or no worse than any other tool: an axe, a shovel or anything. A gun is as good or as bad as the man using it. Remember that.

03-28-2010, 08:34 PM	#4
speedtriplerider Registered Member Join Date: Mar 2010 Posts: 11	carbs i just sold my 81 gs 750 and it had the same carbs. the screws on the bottom are drain screws. there are so many thing that could be wrong if you dont know that much about carbs well good luck.

03-29-2010, 04:59 AM	#6
seruzawa Robby Join Date: Nov 2001 Location: 8501 ft. Posts: 16,803	Tapered screws usually means pilot screws. Try starting at 2 turns out from lightly seated. __________________ I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tanhauser Gate. All those moments will be lost in time, like tears in the rain.

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03-29-2010, 12:29 AM	#5
pyner101 Registered Member Join Date: Mar 2010 Posts: 6	hi its not the drain screw, this screw tapers out to a sharp point and goes verticaly up into the card housing, these are slide carbs

03-29-2010, 05:42 AM	#7
MOKE1K Registered Member Join Date: Jul 2008 Location: Kalapana, Big Island Posts: 3,956	Seru is right, the fuel mixture screw's gererally start out at 2-21/2 turn out. Do you have the airbox hooked up to the bike that could cause a hard start. What about the bike, how longs it been sitting if at all, mileage, compression? __________________ "YOU CAN'T BOLT ON SKILL" "The only thing limiting your bike, is you" We survived Bush you'll survive Obama! "the most fundamental fact about the ideas of the political left is that they do not work. therefore we should not be surprised to find the left concentrated in institutions where ideas do not have to work in order to survive." --thomas sowell

03-29-2010, 11:50 AM	#8
pplassm Founding Member Join Date: Nov 2001 Posts: 3,875	Indeed. Without the airbox, you will be chasing jetting problems forever. __________________ Mongo just pawn in game of life.

03-29-2010, 01:45 PM	#9
pyner101 Registered Member Join Date: Mar 2010 Posts: 6	hi thanks for all your suggestions, i have some k&n filters for the carbs. there are pilot/mixture screws on the side of the carbs which can be adjusted when carbs are on, these pilot/mixture screws are underneath so you have to take the carbs off to adjust. i have never seen this on carbs before so am a bit confused with what they do (been working on bikes for 30 years) i will let you all know if i get it going. thanks all for your help

03-29-2010, 01:50 PM	#10
MopedMarauder Registered Member Join Date: Mar 2010 Posts: 19	Isn't the screw in the bottom with the float bowl the main jet? Maybe that's just for moped carbs.