1986 GS450 carbs

[Anonymous]

I have a set of 86 carbs I want to use on my 83, but just below the choke plunger on the right carb on the 86s is a hose connection that is not on my 83. Can I just plug it or does it need to be connected to something?

[KEITH KRAUSE]

I can't say for sure without a picture. But don't plug it.
It has to be either a vacuum line to the petcock, or a floatbowl vent line.
If it's a floatbowl vent line, just route it so it can breath and not be kinked.
I have to wonder how the 86's jetting compares to the 83's?

[Anonymous]

I guess we'll find out about that jetting in the spring. I'll try sketch a picture and I'll try to post it later.

[Anonymous]

I was just thinking... could it be a connection to some kind of a pollution device? These carbs are from California and the bike isn't.

I'm trying to get this sketch on here.....damn, I'm too stupid.

[sv650]

Pics

If recollection holds, you can't post a pic on this site. You have to upload it somewhere else, and create a link to it. the Pic is then drawn int the page as it is built, rather than being stored on the GS resources server.

SV

[Anonymous]

Looks like #68

http://houseofmotorcycles.bikebandit.com/partsbandit/showschematic~dept_id~720888.asp

[KEITH KRAUSE]

Well, I still don't know what it is. I still wouldn't plug it. That would defeat its purpose for sure. If it's a vacuum line for the petcock, you'll feel vacuum when the motor cranks and its nipple will be the same size as the petcock nipple. If it's a float bowl vent line, you won't feel any vacuum. If you blow into it and the air comes out into the carbs main bore, it's a vacuum. If you blow air into it and it comes out into the float chamber, it's a vent. Of course, you'd have to remove a bowl to tell if it's a vent.
I didn't see a vent line for each carb, so the two float chambers must be connected.
If it's related to emissions in some way, I wouldn't know.

[sv650]

#59 is vacuum line to open fuel tank petcock

#68 looks like the vent line for the float bowls. See Keith's note.

#66 is the incoming gas tee

#74 Dunno????

SV

[Anonymous]

These carbs work perfectly after the mystery hose was plugged. When I left it open. the right carb flooded badly.

[KEITH KRAUSE]

These carbs work perfectly after the mystery hose was plugged. When I left it open. the right carb flooded badly.

Well, I'm glad the carbs are working for you.
It still doesn't make sense that plugging a hose would stop a carb from flooding. A vacuum hose unplugged doesn't cause flooding, same for a float bowl vent line. Not arguing, but something's screwy. :? Sure would like to see those carbs. Again, glad you fixed it.