Uncapped hose under carbs

gkeithly · Jan 26, 2023

Hey y’all, I bought this bike (1981 XS650) end of last season. When changing the oil I noticed this hose that’s just open and not connected to anything below the carbs. Is it supposed to run to anything/be capped? It runs through a t valve to the top of the engine and somewhere else. So that + the oil stains makes me think it’s a vent but i’m not sure. I briefly looked through the service manual and online and didn’t find anything. Attached is a photo

Jan_P · Jan 26, 2023

That looks as the hose going into the Stock filter housing underside. Do you have them ?
I believe it vents oil to the intake

jpdevol · Jan 26, 2023

It attaches to crankcase breather top rear of head, here:

and then also goes to stock airbox

gkeithly · Jan 26, 2023

jpdevol said:
It attaches to crankcase breather top rear of head, here:
View attachment 234438
and then also goes to stock airbox

Yeah I was able to see the line to that breather. Makes sense that it’s a breather and goes to the airbox. I’m not too worried about fixing it before riding season then. Thanks!

gggGary · Jan 26, 2023

Wise to add some sort of a catch can on that hose once the stock airbox recirc system is gone. Makes less of a mess, and well, oil dripping in front of the rear tire, not so good.
There are also various and assorted one way valves that help reduce oil mist there. I'm experimenting with a reed valve in that line on one of the herd.

toglhot · Jan 27, 2023

That hose looks way to small for the breather hose, The breather hose is somewhere around 12-14mm, that looks way smaller

5twins · Jan 27, 2023

No, that's the breather hose alright. I recognize it from having to deal with it on my '83 before I yanked it and the airboxes in favor of pods.

gkeithly · Feb 2, 2023

gggGary said:
Wise to add some sort of a catch can on that hose once the stock airbox recirc system is gone. Makes less of a mess, and well, oil dripping in front of the rear tire, not so good.
There are also various and assorted one way valves that help reduce oil mist there. I'm experimenting with a reed valve in that line on one of the herd.

That’s a good point. I’m surprised I didn’t think about oil on the rear tire since that’s how I spun out a car in the past. I’ll add a catch can to it. Thanks!

5twins · Feb 2, 2023

You haven't told us whether or not you still have the factory airboxes or you've switched to pods. If the airboxes are still in use, simply reconnect the hoses to them. If pods have been installed, many of us fit a power brake check valve to the end of the hose and poise it over the pod. Any oil mist or drops that may come out are simply recycled through the motor just like the original set-up used to do .....

This is the power brake check valve we use, available at most auto parts store for about $5 .....

gkeithly · Apr 4, 2023

5twins said:
You haven't told us whether or not you still have the factory airboxes or you've switched to pods. If the airboxes are still in use, simply reconnect the hoses to them. If pods have been installed, many of us fit a power brake check valve to the end of the hose and poise it over the pod. Any oil mist or drops that may come out are simply recycled through the motor just like the original set-up used to do .....

View attachment 234833

View attachment 234834

This is the power brake check valve we use, available at most auto parts store for about $5 .....

View attachment 234835

Yeah, I do. The hose wouldn't reach back, I ended up repairing it and reattaching it to the stock air box.

Uncapped hose under carbs

gkeithly

XS650 Member

Attachments

Jan_P

Tool Owner

jpdevol

Hacker of Frames,Wires and other things

gkeithly

XS650 Member

gggGary

If not now, When?

toglhot

First class butcher.

5twins

XS650 Guru

gkeithly

XS650 Member

5twins

XS650 Guru

gkeithly

XS650 Member

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