1980 Suzuki GS250 Vacuum lines

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Tower18CHI · Sat Apr 28, 2007 10:59 am

I just got done cleaning the carbs on the bike I just got 3 weeks ago or so. I disconnected the fuel and vacuum lines from the tank to remove it. When I pulled the carbs out, I noticed 2 more vacuum lines that I never disconnected, hanging there open. WTF are these? They weren't connected to anything before, and I can't find anything to connect them to.

That can't be good, right? Open vacuum lines letting not only air in, but unfiltered air. Anyone have one of these bikes and know what these lines go to, or what? The service manual shows the lines on the carb diagram, but doesn't say where they are supposed to go.

#2 Unread post by **Sev** » Sat Apr 28, 2007 12:56 pm

They may be gas tank vents? Designed to allow air in to replace the gas that is being removed.

Tower18CHI · Sat Apr 28, 2007 1:17 pm

Sorry, I didn't explain well. They're coming out of each of the two carbs, not connected to anything outside there. So I have one line going from the top of one carb to the fuel switch, and then 2 more coming out from between the carb throats that don't go anywhere.

flynrider · #4 Unread post by **flynrider** » Sat Apr 28, 2007 4:11 pm

These could be the carb overflow lines. Did they originally route to the bottom of the bike? That would be a good clue. Many carb installations have overflow lines that will dump fuel overboard in the event that the floats stick. This is so you don't get raw gas spilling on a hot engine.

Damian · #5 Unread post by **Damian** » Sat Apr 28, 2007 4:17 pm

I don't know anything about your specific bike, but it sounds like those are drain tubes. They usually drape over the battery. They are there in case you ever go down, the gas in the carbs will drain further aft, away from the sparks. They won't need to connect to anything at the opposite end.

Tower18CHI · Sat Apr 28, 2007 4:23 pm

That makes sense. I didn't see where they were routed originally, I only saw them when I got the carbs off the bike. I'm assuming the reason I didn't see them is because they were routed down...so I'll reroute them tomorrow (have them under the seat right now)

CORSCO · #7 Unread post by **CORSCO** » Mon Apr 30, 2007 1:31 pm

If they are drain hoses, they will be at the bottom of the float bowls. If they are on the side of the carbs, they are vent lines are are supposed to vent to atmosphere. If they get pinched, don't plan on driving very far.