'82 GS550L starting woes - Clean carbs, has spark, no vroom vroom

[Plutoid]

Looking for a little guidance here.

My GS550L has never been an easy starter. Recently it's gotten so bad that I never know if it'll start before the battery dies. Even *more* recently, it's not starting at all. Battery is new and charged, I verified spark on all plugs, starter sounds like it's going. I cleaned the carbs and it's still exactly the same. Once in a great while it sounds like one of the cylinders fires (not enough to get 'er running though.)

I managed by some miracle to get it to start the other day (before carb cleaning), it chugged along in uncharacteristic fashion until I could choke it and rev it up to idle RPMs, ran it until it was up to temp... I even took it for a ride around the block. It ran perfectly, no power loss or anything. I thought I was okay to take the GF for a ride. I pull the key out so I could pop the seat off and mount my saddle bags, clip it back down... no start, same as before. That was the last time it ran.

The plugs were dry and, like I said, I have spark. It feels like - and don't put much stake in this because I'm no expert - that there's nothing drawing the fuel through the carbs and into the combustion chamber. I have an in-line filter and a ****ty plastic valve between the petcock and the carbs. Previous owner installed it. Definitely not stock. When I pulled the carbs the bowls had gas in them so I don't know if that could be the problem or not. The actual vacuum comes from the intake/exhaust strokes of the engine itself, right? The valve cover gasket is torn to ****. It came out in about five pieces and, for lack of a better solution at the time, I put it back the way I found it. There's oil all over the place but I keep it topped up. It leaks, but it's imperceptibly slow. I have a gasket kit on order which should be here any day now. Could that be the cause of a lack of suction?

Bonus stupid question (because I've effed this up before and just need to be sure): The vacuum tube from carb #2 goes to the nipple on the petcock that faces backward, right? ...as opposed to the forward facing one sticking out of the tank that goes to the vent tube? Do I have that right?

[tom203]

Winter is a good time to fix stuff, along with playing catchup with maintenance.
The fitting on backside of petcock should connect to carb #2 for vacuum- it's likely to be slightly smaller than fuel delivery fitting. Easy to check, remove both lines, put petcock lever in "PR" spot and observe fuel exit (hopefully not both). PO likely put on inline filter and shutoff for reason, but with good petcock, they are not needed.
Hard starting???? are you using full "choke" with no throttle input? This could be cry for valve adjustment , so do this when you replace cam cover gasket.

[Plutoid]

Winter is a good time to fix stuff, along with playing catchup with maintenance.
The fitting on backside of petcock should connect to carb #2 for vacuum- it's likely to be slightly smaller than fuel delivery fitting. Easy to check, remove both lines, put petcock lever in "PR" spot and observe fuel exit (hopefully not both). PO likely put on inline filter and shutoff for reason, but with good petcock, they are not needed.
Hard starting???? are you using full "choke" with no throttle input? This could be cry for valve adjustment , so do this when you replace cam cover gasket.

There are three fittings. The main fuel deliver line, the vacuum tube to the #2 carb, and the vent tube that ****es gas all over the floor when you have a bad petcock.

The fullest of chokes, I assure you! I'll check the valves while I'm in there. I'm going to do the petcock and ditch the extra filter while I'm at it.

[tom203]

There are three fittings. The main fuel deliver line, the vacuum tube to the #2 carb, and the vent tube that ****es gas all over the floor when you have a bad petcock.

I have no clue why your petcock has vent line- some Calif bikes had vents on fuel tanks to capture fumes, but a petcock vent seems odd, doesn't seem to be the stock petcock.

[Plutoid]

It's actually on the tank, near the petcock. The tube runs from the tank, down between the boots, under the carbs, and down behind the transmission, emerging by the center stand.

[tom203]

That's likely the overflow line for fuel gauge sending unit ( in case it leaks). You will have to pull tank and investigate.

[terrylee]

Sounds like PO put on shut off because petcock wasn't working properly and or floats maybe getting stuck and not shutting off gas flow. You can try rebuilding petcock, but most don't have good results with that. Just buy a good after market and know that's no longer a issue. Should probably check float needle under floats, may sure they are in good shape and make sure everything is perfectly clean inside there. Not sure what type of floats you have, but make sure they float when put in contanier of gas (no holes in them). Replace vacum line, if you haven't done so. As they said valve adjustment is a must, and be sure carbs. are synced. terrylee

[Plutoid]

I examined the floats, needles and seats, etc. very closely when I cleaned the carbs the other day. All appear to be fine. The thing is this: It doesn't want to start but when it did randomly start the other day it warmed up, idled, and ran around the block like there was nothing wrong with it. Turned the key off, turned the key back on... wouldn't start. Just for funsies I tried starting it today and it sounded like it wanted to pop - like it almost started. This is better than I've seen out of it so far but it still isn't running. :\

[loud et]

I have been watching this thread and see you are struggling. Just to set this up, that 550 that I got just a few months ago was SO perfect and started SO easy when I got it, it was almost as if before I pushed the starter button halfway the bike fired up and just sat there and idled amazingly. SO, that being said, 3000 miles later, I have to admit it is starting to sound like your bike. Hard to start, running a bit rough, when hot is hard to restart...so what happened in the handful of months I have owend it? ....not sure yet. ha ha I know I have some rust in the tank, never personally rebuilt the carbs, and never adjusted tha valves. I am about to tho.
I am not gettng in your face, but you said you cleaned the carbs , but did you clean them exactly as in the carb tutorial on cliffs site? or in Nessism's signiture?
I have new valve cover gasket,carb and intake boot o rings and some berrymans waiting for me to go to work but I have a bad arm and cannot do it yet.
Here is your homework: (as they say)
1 take a picture of that petcock and post it here so we can see this mystery 3 hole petcock
2 make sure your fuel tank is clean and remove petcock and filter screen and verify it is not clogged
3 verify petcock functions properly, if that is some weird petcock and is not working right it needs to be replaced with a brand new one.45-75$
4 Disassemble, dip carbs , install new o rings from cycle o rings. 14$ The tutorial shows you how to bench sync the carbs, set the mixture screws to a baseline setting (2 turns out for example) and set the main idle screw to a baseling setting (2 or 3 turns in after the screw contacts the plate)
5 install new intake boot o rings from cycle o rings 5$
6 install new intake boots if yours are cracked , hard, delaminating or anything 100-140$ (mine are cracking some too)
7 Ensure throttle cable, but more importantly the choke cable is functioning smoothly and not binding. Make sure when you operate the thumb lever it is actually moving the choke mechanism on the carbs.
8 get rid of any bs shut off valve or junky fuel line or inline filters the po put on and read "where do these hoses go" on cliffs site ...make sure all is right. You can install a 4$ paper element fuel filter (wal mart near the spark plugs) for the first few tanks of fuel to catch any fine residue left after the tank /petcock cleaning process.
9 valve adjustment. pretty important to have a nice screamer all the way to 9k rpm's
You may have done some of the above , so that could be skipped, or any item you inspect and clean can be marked off the list. That is at least the general procedure to do a fairly thourough fuel system restore.
One other item that comes to mind with your hard starting issues is to check the timing under the ignition cover. I am not sure about this, but the disc that holds the timing mechanism may have come loose and moved. I have not messed with this much, my other bike that I tore completely down had a mark scribed on the disk from the po, I just lined it up and was golden. yours may be off time a bit.
I love riding my 550, it is so darn smooth and handles just amazing. Even with the giant cruiser bars... comfortable, fast and fun. IF you spend about 200 bucks on the things I mentioned and do all the work right,you can know for sure you are spot on and learn a hell of a lot about basic GS function. You will have a great running bike and be a happy rider. Then a little paint and polish and you will be a proud papa! You could have a 15k dollar Hyabusa there, but if its running like junk, its just junk and not enjoyable at all....as you are experiencing.
Sorry for my rant, I am up and cant sleep. figured I would try and help you out.
Post some pics of your ride ( and petcock) so we can see what we are dealing with .

[tom203]

To loud et; good rant! drives home the message- if you got running problems, fix them and avoid frustration.

[mike_of_bbg]

Just to back up Loud Et, though, I'm going to change up the order a little bit:

1. Check your valve clearances! This is one of the most-neglected maintenance issues with GSes. Overly tight valves are notorious for causing hard starting. You'll have to order gasket, take inventory of installed shims, and probably order several new shims once you figure out what sizes you need. So it can take a few days. That's a good time to:

2. Clean your carbs! Great, your needles and seats are good. That means your carbs aren't going to overflow, but means little about the running of the bike. In particular, the pilot jets and the passages leading to the idle circuit need to be clean, clean. They're most important when the throttle is closed - like when you're trying to start the bike. Once you start riding around and opening the throttle they have less effect. Those carb bodies and jets need to be stripped and spend 24 hours each in the carb dip. That means it's going to take at least 4 days to clean them (given one can of carb cleaner). Again, that's valve adjustment time, plus time to get your o-ring kit.

3. Check your electrical as best you can on a non-running bike! Unscrew the plug caps and make sure the resistance is good there (5k-10k ohms) and not overly high. Trim off 1/4" of wire before you put them back on (for stock wires). Make sure the voltage at the orange/white wires going to your coils is not more than 1V less than the battery voltage. Plugs clean, maybe even new.

4. Ensure all of your carb boots, o-rings (just replace those, they're cheap especially as an add-on for a carb o-ring kit), and airbox seals are in marvelous shape.

5. Make sure you do the bench sync part of the carb clean, and do a vacuum sync after it's all done.

Any of these and all of these can cause hard starting and poor idling. It's amazing yet unfortunate sometimes how forgiving these bikes can be to having multiple sub-optimal situations and just keep running. Once it's not running, there are usually multiple fixes needed.

[loud et]

Thanks Mike, your addition applies to me too. I am still learning. I definately cant wait to see how tight the valves are on mine. I suspect its overdue for adjustment. NOt that I am not going to do the full carb clean route, but just for giggles want to ONLY adjust the valves and see if there is a difference. I did the adjustment on my 16 valve, very easy too. I know 8 valve is not a big deal, I have read up on it a dozen times. This giant cast is killing me as far as doing anything goes. As soon as I go out in the garage, I say "OK, I am gonna get parts xyz off and clean them up" I try and within minutes its just to hard.
Its either my hand is too bulky or the remaining pain stops me from continuing. ha ha
All good tho, I will have a nice running stable in the spring.
Thanks again-

[mike_of_bbg]

Sorry Loud Et to hear you're struggling there. Better to let the bike sit (just make sure you stabilize the fuel!) and let yourself heal.

I sincerely doubt that overly tight valves are the OP's major issue (might be a contributor though) because his plugs are dry. But you've got to get in there and get 'em straight before you can know for sure. And it's a fairly easy job to do. It would be all too easy to get happy about better starting/running, continue to neglect the valves, and end up with burnt valves later...

[Plutoid]

Indeed. That's where the puddles come from.

Any wisdom regarding the starting issue?

[tom203]

Indeed. That's where the puddles come from.

Any wisdom regarding the starting issue?

First thing is to ensure gas is getting thru petcock into carbs- did you inspect petcock for correct operation? did you discover which petcock fitting is the supply line to carbs ( some face forward , some face to rear ) ? Was that third petcock line actually the overflow for the fuel gauge sender? or do you have an unique petcock?