Newbie w/ problems...Gas spilling out of Carbs, etc.

[skirtwheeler]

Howdy All...

I've been watching this forum for a while. I actually just bought my first bike this summer off of a member of this forum. I've been doing some work on it, and I'm having a few issues at the moment.

first, what I have: 1980 GS750L.

The choke cable was broken, so I bought a new one and decided to put it on. So, of course to do that one has to take the gas tank off, and to do that I had to shut off the fuel line. Here's the thing though, someone had tried to spraypaint the petcock black. So it wouldn't move. I sprayed some WD40 on it, and then used a pair of pliars to to shut it off. I was successful in turning it, but the gasflow wasn't affected. It just kept dripping at about two drips a second (quarter note=120 for the musicians out there).

So I took the tank off, disconnecting the lines, and put the new choke on. I also noticed that the carb to airbox boots were pretty much shot, so I took the airbox and filter out. To do this I had to take the carb to intake boots off as well, to create enough room to take out the airbox. I didn't disconnect the carbs completely from the throttle cable or choke cable, but they were free floating for a while. They didn't get turned upside down or anything... I ordered a new set of K and N filters to put on, and I'm waiting on those, but I decided to put what I could back together so I could see how it runs with the new choke cable.

I got the gas tank back on, and then looked at the lines to try to figure out how they went back together. There are four lines I'm working with. One that runs from the tank I'm pretty sure is just a vent line. One I'm pretty sure just runs from in between two carbs to inbetween another two carbs. One I'm pretty sure runs from the petcock to inbetween the two center carbs. That's the fuel line, right? Then there's another that I'm pretty sure runs from behind the petcock down to the front wheel side of the carbs, near where the throttle cable attaches. Did I get that all right, or do I have it connected wrong?

Either way, here's my problem: I've tried connecting the lines in a number of different ways. I have the climmers manual and a service manual, but neither have any clear pictures or diagrams. No matter what I do, when I connect the lines to the carbs, gasoline starts dripping out of the carbs. I haven't put the airfilters on yet, so the carbs are exposed, and just sit there and drip -enough that it pools up pretty quickly, and is a little bit nerve-wracking to work around. What's worse is that when I start the bike it starts spraying gas everywhere.

Did I maybe break the petcock when I tried to turn it? Would that be a reson why the carbs are dripping gas? Too much gas flow? If so, how hard is it to get another petcock. Did I damage the carbs somehow when I was disconnecting them? It's dripping out of all four of them, so I would have had to have damaged all four of them. I'm pretty sure it has nothing to do with the carb to intake boots 'cause it drips even when the bike isn't running. Do I have the lines connected wrong? I feel like I've tried every combination of lines.

I have some other questions too, like is it possible to fix a seal on a head gasket without taking the whole bike appart? I have to ride from Vermont to New Orleans in about a week and a half, and I'm currently losing about a quart of oil every for every five hours of riding, so you can imagine how fun that will be.

Any help would be very very very much appreciated.

Thanks in advance. I've been reading this page for a while, and it feels great to finally be posting on it.

Curtis

 

[tconroy]

Howdy All...

I've been watching this forum for a while. I actually just bought my first bike this summer off of a member of this forum. I've been doing some work on it, and I'm having a few issues at the moment.

first, what I have: 1980 GS750L.

The choke cable was broken, so I bought a new one and decided to put it on. So, of course to do that one has to take the gas tank off, and to do that I had to shut off the fuel line. Here's the thing though, someone had tried to spraypaint the petcock black. So it wouldn't move. I sprayed some WD40 on it, and then used a pair of pliars to to shut it off. I was successful in turning it, but the gasflow wasn't affected. It just kept dripping at about two drips a second (quarter note=120 for the musicians out there).

So I took the tank off, disconnecting the lines, and put the new choke on. I also noticed that the carb to airbox boots were pretty much shot, so I took the airbox and filter out. To do this I had to take the carb to intake boots off as well, to create enough room to take out the airbox. I didn't disconnect the carbs completely from the throttle cable or choke cable, but they were free floating for a while. They didn't get turned upside down or anything... I ordered a new set of K and N filters to put on, and I'm waiting on those, but I decided to put what I could back together so I could see how it runs with the new choke cable.

I got the gas tank back on, and then looked at the lines to try to figure out how they went back together. There are four lines I'm working with. One that runs from the tank I'm pretty sure is just a vent line. One I'm pretty sure just runs from in between two carbs to inbetween another two carbs. One I'm pretty sure runs from the petcock to inbetween the two center carbs. That's the fuel line, right? Then there's another that I'm pretty sure runs from behind the petcock down to the front wheel side of the carbs, near where the throttle cable attaches. Did I get that all right, or do I have it connected wrong?

Either way, here's my problem: I've tried connecting the lines in a number of different ways. I have the climmers manual and a service manual, but neither have any clear pictures or diagrams. No matter what I do, when I connect the lines to the carbs, gasoline starts dripping out of the carbs. I haven't put the airfilters on yet, so the carbs are exposed, and just sit there and drip -enough that it pools up pretty quickly, and is a little bit nerve-wracking to work around. What's worse is that when I start the bike it starts spraying gas everywhere.

Did I maybe break the petcock when I tried to turn it? Would that be a reson why the carbs are dripping gas? Too much gas flow? If so, how hard is it to get another petcock. Did I damage the carbs somehow when I was disconnecting them? It's dripping out of all four of them, so I would have had to have damaged all four of them. I'm pretty sure it has nothing to do with the carb to intake boots 'cause it drips even when the bike isn't running. Do I have the lines connected wrong? I feel like I've tried every combination of lines.

I have some other questions too, like is it possible to fix a seal on a head gasket without taking the whole bike appart? I have to ride from Vermont to New Orleans in about a week and a half, and I'm currently losing about a quart of oil every for every five hours of riding, so you can imagine how fun that will be.

Any help would be very very very much appreciated.

Thanks in advance. I've been reading this page for a while, and it feels great to finally be posting on it.

Curtis

Go to www.bikebandit.com and look up your carbs and you will find what goes where.If you are not using the stock airbox you will have to rejet for the pods which means your carbs will have to be cleaned and run right first.Get it running good before you jack with putting the pods on.I think you have the lines hooked up wrong also. Your vacumn line should go in front of your carbs and the fuel line is in the middle of #2and #3 carbs.There is two vent lines that are for the float bowls in between 1 and 3.if you have the cv carbs.Look at your manual closely,it should show you therealso.

 

[skirtwheeler]

The airfilters mount on to each of the carbs individually. Will I still have to rejet? I'm sorry, I'm totally new at this. I've never worked on anything with a motor before. What is rejetting, by the way? What I was planning on doing was just taking off the old air box, and then putting the new filters on? Will my bike then not run properly?

So the vaccuum tube is the tube that comes down from behind the petcock, right? Then the fuel line comes out of the petcock and goes in between #2 and #3, right? Then there are these vents between #1 and #2, and another between #3 and #4... they look like they should have a tube on them, and indeed there is a tube attached between #3 and #4 that was there before I took everything appart. What I have it doing at the moment is running from between #3 and #4 over to the vent between #1 and #2. Is that right?

Thanks for your help

Curtis

 

[skirtwheeler]

Oh, and thanks for the link... would you mind helping me use it? I can only find new parts for sale on that page. My carbs are Mikunis, but they are from 1980. If they are the originals, which I'm assuming they are, they should be BS32SS. I can't find those on the page. All of pictures of Mikuni carbs that I found were single carbs that weren't mounted.

Thanks a million.

Curtis

 

[hwb120240]

http://houseofmotorcycles.bikebandi...el_dept_id~988006~model_dept_name~GS750LT.asp

BTW: The vent lines on the carbs just vent to open air, so take the line loose that you connected between the carbs. Tubes are routed down right side on my '79.

 

[robertbarr]

There will be a drain hose originating from the area of the fuel gauge sender. This gets connected to nothing -- just keep it out of the way, like the vent hoses from the carbs.

No matter how well the petcock works or doesn't work (in stopping fuel flow), fuel shouldn't be leaking from the carbs.
I have no idea how you'd change any aspect of all four carbs just by changing a choke cable, but keep in mind how old these carbs are.

If fuel is flowing (or even dripping for any length of time) with the engine off, there's a problem with BOTH the petcock (unless it's switched to the 'prime' setting) and one or more of the carbs. These are very common problems and should be attacked separately. Fortunately, these are usually easy and fairly inexpensive to correct, but you have to be thorough.

It's very frustrating when a change to system 'A' inexplicably changes something in a completely unrelated system, but it's a really old bike with ancient elastomeric (rubber, etc) parts.

 

[jeeptrix]

I had a similar problem with my GS1000. The fuel flowed out the bottom of the carbs. The floats were stuck from sitting so long. Take the bowl off and clean them out.

 

[skirtwheeler]

thanks y'all

thanks y'all

Thanks everyone for your quick replies. I'll be working on it today, so I'll let you know how it goes.

curtis