84 Suzuki GS550ese Fuel Tank & Carb questions

[JaeArr]

Hey all, If anyone out there is knowledgeable with this specific model bike or just carbs & tanks in general any advice would be greatly appreciated. Currently trying to figure out connections on the tank and carbs and what they correspond to, the carbs are the 2 into 4 model mikunis. Seriously any help would be appreciated haha.

[A100man]

https://www.cmsnl.com/suzuki-gs550ese-1986-g-usa-e03_model34258/partslist/BLCK0007.html#.YWAw_9XMKUk

I'd wager 59 is vacuum for the tap and 60 is fuel in, 58 meanwhile provides flow of fuel to carb 2.

interesting not seen that type of 'dual carb' on an IL4 before..
____________________
Now: A100, GT250A, XJ598, FZ750, SL1000

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600, Skorpion

[JaeArr]

im right on board with you for 58, 59 & 60 got those connected to the petcock on the tank, my issues start where 59's port has a duplicate on the left carb is that supposed to be connected to anything should it be capped off? IDK. The fuel tank has what I believe is a float and fuel sender with a port coming off of it where do I connect that to? IDK theres also a port sticking out of the top of the underside of the tank my guess is its a breather but i have no idea as when i picked up the bike it was connected to another random port on the carbs im just not sure.

[A100man]

IDK either..

top of tank will be a breather I expect which might not need connecting just free to air. BUT if teh bike is Californian spec then often they seem have odd arrangements to limit emissions -are you American?
Post a picture -
____________________
Now: A100, GT250A, XJ598, FZ750, SL1000

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600, Skorpion

[JaeArr]

Yep from the States for all that's worth nowadays lol.
After literally a whole day of internet sleuthing I think I've got it figured out for the most part. 59 was vacuum, 60 is actually vent lines which is why its on both carbs and the port next to 58 is the actual fuel in. The fuel sender unit is supposed to go into an overflow that is missing on the bike but unnecessary in the long run and yes top is a breather. So if I am correct in all of those assumptions then I have the bike properly connected and now the reason its not running is something completely different lol. Most likely I have the carb jets set improperly. This model of carb does not have fuel air mixture screws so any errors are more than likely internal.

Tank: Green dots are fuel gauge/sender I believe, Purple is vacuum, Yellow is fuel, Orange is breather

Carbs: Blue dot is vacuum, Red are the vent lines I believe, Yellow are fuel in and flow pipe.

[A100man]

On bikes like this (I guess this has been standing a while) the carbs need a thorough clean of EVERY passageway. Check youtube for videos etc..

Even if the PO tells you they have been ultrasonically cleaned I don't care. You have to do this job yourself unless you have a well trusted pro do it for you..
and they are few and far between.

I guess you have a spark.
____________________
Now: A100, GT250A, XJ598, FZ750, SL1000

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600, Skorpion

[JaeArr]

That's exactly what I did, carbs were completely pulled apart when I first got the bike, this is my third time taking them apart and cleaning them, every needle, jet, washer, oring, & tube was extracted (except for pilot jets couldn't get them out and haven't ordered replacement jets yet so didn't want to risk damaging them before I had new ones but they were sprayed to hell and back to make sure they were clear and liquids were flowing thru them) cleaned with carb cleaner then I ultrasonic'd em myself before reassembly and reinstall on bike. And honestly it sorta seems like the bike was running better before I corrected my improper fuel hosing situation I could get it to idle for a bit longer then than now so I'm at a loss here.

I've got spark & compression, fuel is flowing thru the bowls and every so often I can get it to idle, it'll usually die out after a few seconds but I can keep it going by giving it throttle but the moment I let it go it just dies. Also strange it'll start up only with the choke closed I've never had it start with the choke open hmmmm...

[A100man]

People will always say that valve clearances need to be in spec before you 'adjust' carb settings(or in my experience if you have starting issues).

Easy on these motors I think as no shims involved afaik..
____________________
Now: A100, GT250A, XJ598, FZ750, SL1000

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600, Skorpion

[Robby]

Places I would be looking for an old bike that doesn't want to idle:

1. The idle circuit. When cleaning the carbs, did you remove the mixture screws and blow though with carb cleaner, then reset the screws to factory settings (or factory settings with an extra half turn for luck, which I usually do).

2. Is it running a fuel filter? I have had trouble in the past with vacuum fuel taps and fuel filters. Not running a filter has solved this problem.

3. Throttle shaft seals. Those seals are 40 years old, and probably hard and leaking by now. This lets some air in. Doesn't make much of a difference when riding - it's a very small amount of air - but does make a difference at very low power, high vacuum situations, like idling.

Also worth making sure that anything made of rubber is still flexible and whole. Inlet rubbers and vacuum caps are favourites for air leaks.

Old carbs are a pain in the arse. My preference is to replace everything that isn't made of metal to get a decent baseline, then occasionally trace down problems in the replacement parts. I prefer to use the original jets after a really good clean, some replacement parts aren't the size they claim to be.