Gas Not Leaving Float Bowls

[DanTheKid]

Hello all. New forum member here. I picked up my first GS a couple months ago. This is my first project bike. I'm sorry if this question has been asked before, I couldn't find it anywhere.

It is a '82 GS550L. It has good spark and I believe decent compression, as it will turn over and run when starting fluid or even gasoline are sprayed down the carb throats.

Won't turn over on its own power. Not even a cough. I've cleaned the carb dipped the CV carbs and cleaned everything backward and forward. When I pull the plugs after trying to run it, they are dry, but if I loosen the valves on the bottom of the float bowls, a decent amount of gas comes out. It seems the gas isn't making it out of the float bowls. The pilot jet and main jet of each carb are clean. The PO must have replaced the rubber as all are pliable and well fit. I doubt there is a vacuum leak.

Any and all advice/tips would be greatly appreciated.

 

[DanTheKid]

I apologize for not mentioning, as far as I can tell, everything is stock on the bike. Stock airbox, stock exhaust, jets, etc.

 

[Guest]

Your engine is basiclly an air pump. pulls air in and pumps it out. You need to check the air filter box seal, rubber boots and seals to make sure they are seating properly and you don't have a huge air leak problem. Might want to check the valve adjustment as well. Make sure they are opening and closing right. Check your compression to make sure, I believe it has decent doesn't cut it...make sure. Check the plugs, are they sparking? At the last resort, recheck the carbs, make sure the main jets are clear. Process of elimination.

 

[DanTheKid]

I appreciate it.
The plugs are firing. I'll double check the compression. I was confident the problem was with the carbs as a couple squirts of gas down the airbox got it to fire, no problem, but I will go back and start double checking everything. Thanks for your response.

 

[Big T]

Dan, your assumption is correct
If it starts with spray, it's not getting any gas
Did you follow the carb rebuild tutorial when you dipped them?
Is your air box connected?

 

[Steve]

How long were the carbs dipped? What dip did you use? If you followed the directions on the can, you need to do the job over.

The directions on Berryman's and GUNK dip say to immerse the parts for 15-30 minutes. Those directions were probably written back when the chemicals inside the can could actually do the job in that amount of time, but the EPA and other "safety" weenies have reduced the effectiveness of the chemicals without re-writing the instructions.

The instructions should read: "Immerse the parts for 15-30 HOURS."

Did you replace the o-rings in the carbs? If all you did is remove the pilot and main jets, then throw the carb in the dip for a few minutes, you will have to do the job over.

.

 

[DanTheKid]

Ah. I did completely pull apart the carbs front to back to dip them. Used new o-rings and reconnected the air box. However, I followed the directions on the label. This is good to know. I?ll redip them for much longer. Thanks for the help.

 

[Steve]

Make sure you have EVERYTHING out of the carbs, including the "choke" plungers.

.

 

[bobgroger]

On CV carbs there is a passage in the float bowl that feeds the choke with fuel. No choke = no start with CV carbs. The orifice is VERY small, maybe .025 inch and easily plugged. Page 51 here: https://thexscafedotcom.files.wordpress.com/2014/06/mikuni_bs-cv_carburetor_rebuild_tutorial.pdf

 

[fbody_mike]

I believe it also possible to use the wrong float bowl gasket and block those "choke" passages.

 

[Steve]

That would be very difficult. :-k

The opening is near the bottom of the float bowl, the pickup tube goes down a hole in the edge.

There is no way a gasket is going to block anything and still allow assembly of the bowl to the carb body.

.

 

[fbody_mike]

Your right, not really the choke passages. But isn't there an air vent passage the passes through the float gasket on the same side as the choke tube?

 

[Steve]

Yes, there is a passage, but I never have figured out why. :-k

At the top of the chamber, near the center of the carb body, is the vent port that is directly vented to atmosphere.

.