GS850 Gas tank fuel line help

[prpldude]

I know it has to be on here... I have spent over an hour searching but cannot find the answer to my question.

If the answer to my question is already on here please give a link. If it is not any help would be appreciated.

I have a '80 GS850GLT. I took the bike apart last November and finally getting it back together.

I was putting the fuel tank back on and I only have 1 hose coming from the carbs, small thin one looks like it hooks to the petcock. There is another "nipple" coming off the petcock that is bigger, and two coming off of the tank itself. One of the ones coming off of the tank looks like it is coming off of the "fuel level" thing. The other is coming right out of the tank.

I need help knowing what goes where.

Thanks in advance and again sorry if this is already on here. I'm desperate to get this done tonight :0)

Marc

[tas850g]

the small hose coming from the carbs is a vacuum line to the smaller nipple on the petcock. The bigger nipple on the petcock is your fuel line to the carbs. B/C i have the vm carbs i don't know where the fuel line to the BS carbs go, my goes in between #1 and #2 carbs.

The fuel sending unit has one hose coming from it and it is a vent hose, i believe, that goes to the right side of the airbox and travels down with the other vent hoses from the carbs.

I don't know what the other line coming out of the tank goes to. I hope i'm not comparing apples and oranges with my vm carbs compared to the bs carbs but the hoses are similar.

Hope this helps some.

[kilog55]

you should have a large line with a coily wire on it and a small vacuum line like shown here thanks to Bikcliff's site

http://members.dslextreme.com/users/storagecliff/images/hose_locations.html

[prpldude]

Thank you for your help. The fuel hose off of the carbs got tucked down between the carbs when I put them back on.

Started it up tonight and ran great.

[Dogma]

That's my bike exactly. In stock condition, there are 3 hoses from the tank and two wires. You didn't mention wires, but I'll cover that anyhow.

The first hose is from the fuel level sending unit at about the middle of the is an emergency drain line in case the fuel level sender develops a leak. Route this past the back of the engine, in front of the rear wheel. The wires from the fuel level sending unit connect to harness just about where the left side cover meets the air box (or where shown in the link above). Match the colors, or the gage will read strangely (always full, or always empty, can't remember which).

The next hose to think about is the fuel line. It comes up from a T between the #2 and 3 carburetors. I hope it's already there, because it's very difficult to get the hose on with the air box mounted. This connects to the large nipple on the petcock (the higher one/closest to the tank). Make sure this has no kinks (or filters) and does not go up before coming down. That can trap an air bubble and make trouble.

The last hose comes from the from side of the #2 carb (2nd from your left knee) and connects to the bottom nipple on the petcock.

You have the infamous leverless 1980 petcock. To prime the carbs, use a screwdriver to set the slot horizontal. Turn the engine over a few times with the starter to establish vacuum. Go do something else for a minute. Set the slot vertical for the "run" setting, and the bike should start.

Is your petcock original? If so you need to verify correct function. At this age, it's probably bad. Malfunction can lead to anything from stranding you on the side of the road (not holding vacuum) to hydraulic lock in #2 cylinder and possibly destroying the engine (perforated vacuum diaphragm leaking fuel into the intake).

To test: take the hoses off the petcock, and have some fuel in the tank (1/2 gallon at least). Set to "run". No fuel should flow, until you are putting vacuum on the vacuum line by sucking on it. You should feel a definite stop when you suck on the vacuum line, but I proved to myself that this is not conclusive proof of a good petcock. It could still leave you stranded as if you have no gas, when you know there's still a gallon in there. Fuel flow should stop completely when you release the vacuum. Set to prime, fuel will continue to flow when you release the vacuum. If you taste even a hint of fuel in the vacuum line, you have a bad petcock. If fuel does not freely flow as described, you have a bad petcock.

Word on the forum is that the rebuild kits are useless. A new petcock from Z1 is about $60. Call 'em if you can't find it on their site. Some people like to replace it with something that has a lever, but you only have to deal with it once a year, or as often as the carbs are empty. If you have a new one, you don't have to worry about it failing when you're more than walking distance from home. At this age, it's due to fail.

I guess that should just about cover it.

[kilog55]

so your saying dont run a fuel filter then? any reason why?

[BassCliff]

Hi,

If you have a clean tank there is no need for a fuel filter. The screen at the top of the petcock is all you need. If you must run a filter, be sure it is designed for "gravity fed" fuel systems, like a lawn mower fuel filter. Automotive fuel filters rely on pressure from the fuel pump. Since there is no fuel pump on our bikes, these filters can lead to fuel starvation.

I, for one, do not use a fuel filter.


Thank you for your indulgence,

BassCliff

[kilog55]

well when i did my mods guess what my fuel filter was on wrong from the PO he had it on backwards flow was pointing to the tank not the carbs so i reversed it, but my fuel is very clean as is the tank so i should replace the fuel line with a single piece then

[prpldude]

Thanks for your advice all. I got it all back together. I have some things to do so I will be checking my petcock and doing valve adjustment and spark plug check this weekend.

thanks again,
Marc