GS 450 semi-automatic carb question

[dkruitz]

We're rebuilding these, from a bike that's been sitting a while. There are three hoses coming from it, one for fuel, one for vacuum to the petcock, but there's another coming off the airbox side of the #2 carb that we can't figure out where it goes. The old hose has an indication that it was on a a barb of some sort, but we can't figure it out. Any ideas?

[SPARKSS]

We're rebuilding these, from a bike that's been sitting a while. There are three hoses coming from it, one for fuel, one for vacuum to the petcock, but there's another coming off the airbox side of the #2 carb that we can't figure out where it goes. The old hose has an indication that it was on a a barb of some sort, but we can't figure it out. Any ideas?

Heck I just have to ask..........What does "semi-automatic" refer to on this bike?
Hose off of the airbox (inlet) side of the carb.......between the carb and filter........hmmmmmmmm if that was a truck or other industrial engine I'd be looking for the filter restriction gauge (or perhaps even a quick start setup for primed fuel or ether).

[dkruitz]

It's a semi-automatic transmission, with shaft drive. Also just found out it's completely clutchless - what we thought was the clutch lever was an alternate handle for the rear brake! Very odd bike!

[eliotsajerkface]

imagine how confused i was when i got my 450ga home, never seeing one, and the throttle was upside down on the left side.

[eliotsajerkface]

i also just had this problem yesterday. the vaccum tube goes to the small barb on the petcock, the one off the T goes to the fuel line on the petcock, the one coming up from the side of the airbox goes onto the tank for what i was told, an overflow in case the seal leaks on the gas gauge, and the other lays across the airbox.

[dkruitz]

There's no gas gauge on this - I'll check the third tube to see if it fits on the airbox somewhere.

[duaneage]

Might be atmopheric vent for the carb. The carbs have a vent tube that puts air pressure over the bowls. Some people remove the vent hoses from the cab to improve drivability, others leave them on. I didn't see a difference with mine either way so I left them on.

There was a overflow catch on tanks with fuel gauges designed to carry fuel to the ground if the sending unit in the tank leaked. Many people think this is a vent for the tank, it actually is a safety feature. See if your tank has a sending unit, it may have one even if the gauges don't hve a gauge for fuel.