Which Lines Go Where?!

[Guest]

Hello fellow GS enthusiasts!

I am embarking on my first restoration project with my first motorcycle. I figured what better way to know the ins and outs of my own bike than to restore one. So far, I've been able to find most of the information and tutorials I need, using a bit of critical thinking and experimentation here and there. However, I'm having an issue that I can't seem to find remedy for.

I have just replaced the carb intake boots to the manifold and am ready to re-install the carbs. When I bought the bike, all of the lines to the carb had been disconnected. The previous owner had begun to restore but lost interest. I have been able to determine that the rear center nipple goes to the larger nipple of the petcock, and the front center nipple is the vacuum line which goes to the small petcock nipple. However, there are two more nipples on the carb (one on the far left and on on the far right) that I have no idea where they go. There is a nipple on what I am pretty sure is the gas level gauge. There is also a large hose that comes off the top center of the engine that I have no idea where to connect to.

Please help! I have everything ready to get the bike running (not moving, but running), but I cant figure out where to connect these dang hoses!

[JEEPRUSTY]

year and model of bike please?

[2BRacing]

If your carbs have the "flat" tops (CV type carbs), then the following will help you:

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

[JerbGas]

Whoops! It's a 1980 GS 550 L with the flat top CV carbs

[JerbGas]

That site is great, but the pictures arent showing

[Steve]

Since you can't see the pictures, ...
The two hoses on the far left and far right are vent lines. They get draped over the back of the airbox or under the seat. If you have a small rectangular bracket on top of your air box lid and have wondered what it is for, it's to hold the vent hoses.

The nipple on the fuel sender is for a hose that will direct any leakage away from the hot engine. It runs back, along the frame, to the back of the engine. The line might be long enough to go between the engine and the swingarm.

The large port on the top of the engine is the breather. It should be connected to a similar port on the top of the airbox, ahead of the carbs. The air flow through there will suck any fumes from the top of the crankcase through the carbs and burn it. Just an early form of emissions control.

You are correct about the lines to the petcock.

.

[Brendan W]

At a guess somebody had the carbs apart and forgot about the vent lines when ganging them up again. It's almost impossible to get them back on with the carbs together.
If you're running pods you'll need to get creative with the breather hose - a catch can or something - otherwise everything back there will get covered in oil eventually.

[JerbGas]

Since you can't see the pictures, ...
The two hoses on the far left and far right are vent lines. They get draped over the back of the airbox or under the seat. If you have a small rectangular bracket on top of your air box lid and have wondered what it is for, it's to hold the vent hoses.

The nipple on the fuel sender is for a hose that will direct any leakage away from the hot engine. It runs back, along the frame, to the back of the engine. The line might be long enough to go between the engine and the swingarm.

The large port on the top of the engine is the breather. It should be connected to a similar port on the top of the airbox, ahead of the carbs. The air flow through there will suck any fumes from the top of the crankcase through the carbs and burn it. Just an early form of emissions control.

You are correct about the lines to the petcock.

.

Thanks that is perfect!

[JerbGas]

At a guess somebody had the carbs apart and forgot about the vent lines when ganging them up again. It's almost impossible to get them back on with the carbs together.
If you're running pods you'll need to get creative with the breather hose - a catch can or something - otherwise everything back there will get covered in oil eventually.

Not running air pods. I was going to, but I decided to keep the stock airbox. Re-jetting the carbs would be needed and I hear it takes a lot of trial and error to get it right. As my main goal is to get the bike road ready first, I figured I'd tackle that somewhere down the line if I still want to.