throttle body vacuum pipe

[mark1971]

guys just got back from trip away on bike and after washing the beast my brother turned up,,so we gets talking about my new bike and i start it up for him to hear and i notice a hissing noise.....after a quick search its coming from both throttle bodies...underneath each one at the front i have a small piece of rubber pipe,,about 10mm long,,,going nowhere at that length,,,,,the bike seams to run well but just seems odd.....just wondering in the bikes original state should these pipes be longer and attached to something......the bikes a 99 1150gs....
thanks in advance

 

[Two wheels good]

The cap for the vacuum take-off point is leaking. That's where vacuum guage is connected to balance throttle bodies. Most likely the caps have been replaced by a piece of rubber tube which hasn't been sealed properly.
See part no. 10 in diagram here.
http://www.realoem.com/bmw/enUS/sho...21-BMW-R_1150_GS_00_0415,0495_&diagId=13_0840

Get the proper cap or seal the piece of rubber tube with a blob of silicon. But don't do it in situ; you don't want to clog the airway.
Also check clamps on air intake are tight.

 

[Steptoe]

The cap for the vacuum take-off point is leaking. That's where vacuum guage is connected to balance throttle bodies. Most likely the caps have been replaced by a piece of rubber tube which hasn't been sealed properly.
.

Some bikes did use a tube fitted as a blanking plug and the tube is sealed.

 

[mark1971]

many thanks for your replies,,,very much appreciated