1977 GS550 fuel problem

[secroot]

recently got the GS550 and it was running fine until i removed gas tank to replace clutch cable---after putting tank back on, it is only running on cylinders 1 and 2 even though plugs 3 and 4 seem to be getting spark----i am especially interested in ideas to check without assuming something is wrong inside carbs 3 and 4----petcock is working ok including prime and vacuum ok in run and reserve----it was running fine before on all 4 cylinders----help please???? cletis root---southern illinois

[trippivot]

turn the fuel on at the tank and drain the carb bowls individually. bike running or on prime.

this is to verify where the fuel is and is not. (like a kink in the hose)
I use a spray can lid to catch fuel or a rag


it will not explode into flames if a little gets on the exhaust pipe. just smoke up a little.

[almarconi]

It could be coincidental that you started having problems when you removed the tank. Did you check for pinched wires when replacing the tank. Removing the tank could have dislodged some crud that is now stuck in your carbs. This happened to me when I replaced the petcock on my bike.

Did you check the plugs on cylinders 3 and 4? Are they wet with gas?
If the plugs are not wet then your carbs are most likely the problem.

What voltage are you getting at the coils?

[secroot]

how do you drain the carbs individually?

[Nessism]

Drain plug on the floatbowl.

[Guest]

I bet you kinked the fuel line.

[BassCliff]

Greetings and Salutations!

Hi Mr. secroot,

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BassCliff