I,ve just bought a gk71f , 1987 model,after taking the tank off i find a pair of Siamese pipes coming from the carbs but nowhere to put the single end. Seeing a nipple poking from the bottom of the tank ,i fit it on there, not thinking it might be a water drain from the filler cap. When i came to it today,carbs were full of water problem is where does this pipe go, on my old gsx250 the vacuum pipes go to the petrol tap but this bike only has one connection on the tap

I,m thinking its an aftermarket fuel tap & it should be a vacuum tap with 2 connections, can anyone confirm. That ? If i do keep. This tap i,ve got, what should i do with the pipes from the carbs, blank them or just leave them to breathe?

on my fuel tap I have a small vacuum hose that leads to the top of the second carb (second from the left as you are sat on the bike). This single carb provides enough vacuum to open the fuel tap in the "run" position. The other hose on the fuel tap is obviously the fuel that goes into the top of the carb. The nipple on the bottom of the tank is indeed a drain hose for the fuel cap, basically you attach a pipe to that and it runs off to the bottom of the bike to drain safely away.

Cheers pal, i,m thinking yours is a gk73 with 4 carbs,mine & the earlier ones have 2 twin choke cv carbs, i,m presuming yours are also cv carbs if they have a vacuum pipe to the fuel tap.i,ve got a problem with it not wanting to idle properly once the chokes off & thought it might be something to do with the vacuum. Pipes not being attached.