Help with carb tuning 78 gs550e

[enriquev9]

I finally got my 1978 Suzuki GS550E assembled and started. Now I am beginning the frustrating process of fine tuning. I could use some direction with the following issues

1) [NODE="2"]Forum[/NODE] carb leaks fuel out if the overflow tube intermittently. It usually happens when I turn on the fuel from my fuel bladder. After a while it will stop, but then spill fuel every 3-5 min then stop then start again. After I warm up the the bike it stops. But then leaks again after I shut the bike down. Then sometimes the [NODE="3"]Blogs[/NODE] carb starts to leak but that one is less intermittent. Does this have anything to do with the vacuum of the carburetors? (I ask because [NODE="3"]Blogs[/NODE] cylinder wasn’t firing properly until I capped the vacuum port) Or is it just a bad needle valve

2) I have a hanging idle when I rev the bike. I’m trying to adjust the air mixture screws and when I give the throttle a quick rev it stars the hang then eventually comes down. Is this a sync issue or a mixture issue.

3) would like to sync carbs but my motion pro carb sync lost all its fluid when I started the bike to calibrate the tool. I’m super upset with that especially after following all the set up instructions. What do you guys use to sync carbs? (I know this is an important step)

here is a list of some of the work I’ve done to restore my bike
1) installed new intake o-rings and intake carb boots
2) Cleaned all carbs with carb dip and sonic cleaner
3) replace o rings only using cycle o rings
4) adjusted float heights (24 mm if I remember)

any direction and steps to correct these problems would be deeply appreciated.

 

[Big T]

1. Fuel height is more important than float height. Check that 2. Hanging idle is air leak, or improper cable action. Where do you have the pilot air and fuel screws set at?
3. Maybe you forgot the restrictors? You can't get a refill?
Morgan Carb tune

What is your air filter and exhaust?

 

[enriquev9]

I am using the stock air box and filter. I even used weather stripping on the air box cover to help with sealing. I am also using the stock exhaust with no mufflers as they were rusted out. Planned on welding new mufflers when I got the bike running.

i used the VM carb rebuild guide from the BikeCliff website. Set the Pilot fuel screws to 1 turn out. The pilot fuel screws to two turns out (as per the maintenance manual). I was using the technique in the guide were I would turn the pilot air screws out until I heard an increase in RPM. I am having to turn the number 1 pilot air screw out the most to get an increase in rpm. Cylinder 1 and 2 are running rich on the spark plugs and 3 and 4 look good. (Will post pics of the plugs)

The throttle snaps back into place quickly so I doubt it’s cable action unless there is another way to check the cable action. I will see if there is a leak by spraying water on the intake boots etc. However I think the issue is more carb syncing from what I can tell in my searches.

what do you use to check fuel level in the bowls?

 

[Big T]

Z1 Enterprises sells the adapter that replaced the float bowl drain screw.

 

[enriquev9]

Went back today to see if the carbs still leak out of the overflow. To my surprise….they’ve stopped. Should I still consider replacing needle valves for peace of mind?

EDIT
Number three carb is now leaking intermittently. Especially when I shut the bike off. I went ahead and took the carbs off. Fuel level must have been super high for them to overflow. I rechecked the float heights and they are at 24 MM. Something isn’t right. Even the float bowl gaskets were soaked in gas.

will also order parts to check fuel height in the bowl