gs650 carbs... What are these hoses and where do they go?!?!

[gous44ls]

I have an 82 gs650 that i bought from a friend of mine for 50 bucks. Amazingly everything works (lights, horn, starter, etc) but i does not run. The carbs that were on it were a mess so i bought new used ones on ebay. The carbs that were on the bike only had two lines coming off of them, fuel and vaccume. There were two unused nipples however. I got the new carbs and there were two hoses coming off those nipples and i dont know what they do or where they go. So i put the carbs on and filled the tank with gas and it would not start. The only way i can get it to fire up is to spray gas directly into the carbs and it runs breifly and dies. Should the bike run without the hoses? Also there is no airbox on the bike. I would love for someone to help me with my problem. I'm 15 and still learning!

[Macmatic]

Gous,

Congrats on getting a GS for a learning project, you'll find lots of help here and have a great bike when you're done.

Those two hoses are most likely vent lines from the bowls and it should run without them, some people take them off on purpose. You need a vacuum line going to the petcock and a fuel line. I think the vacuum hose connects to the front of #2 carb and the fuel connects between 3&4 at the back.

Are you sure you're getting fuel out of the tank? If you don't have the vacuum line hooked up and the petcock is set to "run" or "res" you won't get fuel. You will get fuel on PRI but you shouldn't leave it like that because you can flood the carbs and fill the engine with gas.

You pretty much have to have the airbox in place with stock jetting, from what I've read trying to start it without the airbox is going to do nothing but eat up your time.

Search the forum for "bench synch" and get instructions on how to do that before you spend much time messing around with it. If your carbs are way out of synch you won't get very far.

While you have them off check your intake boots and o-rings, they are a common failure. PM me if you need new o-rings and I'll send you a set of viton rings (if you live in the US) as a "welcome to the club" gesture.

(edit) You might want to search for "robert barr" too. He sells o-ring kits for the carbs, $10 and well worth it. For about $20 you can have the o-rings for inside the carbs and a can of carb dip. Then follow the directions on the main page of the site here (garage section) on rebuilding your carbs and you'll learn everything you want to know about them and much, much more.

Once you get the basic setup done you'll need to buy/borrow a carb balancing tool too.

/\/\ac

[gous44ls]

the carbs came off a perfectly running motorcycle and were pulled off in august 05 so they should be clean and tuned fairly close right? And why does it run if i spray gas or starter fluid directly into the carbs? and what does the airbox have to do with making the bike run? Im a newbie and thanks for all your help!!! Im located in cincinnati ohio if u know anywhere that will fix it for cheap.

THANKS!!!

[gous44ls]

oh and i have the vaccume line hooked up the petcock and its on res with good gas in it. I know the bowls are filling up with gas because i have a fuel filter on it and i can watch gas go thru it.

[Macmatic]

the carbs came off a perfectly running motorcycle and were pulled off in august 05 so they should be clean and tuned fairly close right? And why does it run if i spray gas or starter fluid directly into the carbs? and what does the airbox have to do with making the bike run? Im a newbie and thanks for all your help!!! Im located in cincinnati ohio if u know anywhere that will fix it for cheap.

THANKS!!!

Well the bike runs when you spray fuel of some type into the carbs but not when just cranking it over because it isn't drawing fuel out of the bowls on its own.

Try putting the airbox back on if you have it. These bikes need some restriction on the upstream side in order to work properly, at least thats the way I undestand it. My own GS750EF runs like crap if I even take the airbox lid off!

If you don't have the airbox you'll have to find some way to restrict the intake for testing. Maybe you could take a flat board (remove anything loose first!) and hold it across the back of the carbs leaving just a small opening and then try to start it that way.

As for the carbs off ebay... well they came off ebay so they might have just come off a perfectly running bike a few months ago or they might have come off a bike thats been sitting in a shed for ten years because someone rebuilt the carbs and never got it running again.

Since you don't have the airbox on it should be easy to pull them off and see if they appear to open at the same time and evenly. Look through them and open the trottles just a crack and see if the gap you can see light in is the same across the carbs. Also check to see if the slides move freely.

/\/\ac

[DaveDanger]

Those two "unused nipples" are vents to the atmosphere for the float bowls. They originally had a pair of hoses attached that routed up and over the airbox and down towards the back tire like the battery vent and various other waste vent hoses do. I recommend that you put a hose on each one with at least enough length that allows it to go up and over the airbox, and down a little bit. If those nipples are left open with no hoses installed, they'll suck up rain at the very least. They are not active vacuum sources, but they do allow the float bowls to breathe. There is therefore at least a tiny amount of air inflow there. I found out the hard way that if those nipples are plugged or capped solidly, that the carbs will overflow huge amounts of fuel into the airbox. Stoopie ole man!

[duaneage]

Set the fuel valve to the PRI position, wait 20 seconds and try again. If it starts your petcock is bad and needs to be repaired.

You could also try this.

remove the fuel line from the petcock and put another hose on it leading into a gas can. Turn the valve to PRI and see if gas runs out.

The screen inside the tank could be plugged up if no gas comes out when you select PRI.

remove one of the fuel bowl drain screws adn see if gas runs out, if not \you know where to start looking.,

[gous44ls]

thanks for all your help! i got it running yesterday. There were 4 bolts, one on each intake boot, for vaccume tests that i didnt put back in. I checked the petcock and it works fine and the bike started with the choke on. all it needs now is a rejet for some after market air filters or the stock air box put back on and i should be good to go!!