Gas tank fill up

Joined
Sep 4, 2013
Messages
8,111
Location
Cleveland
Bike
2010 ST1300
When I had the tupperware off my ST this past winter, I saw that there are a couple of small hoses leading from the upper tank to the lower tank(?). They appeared to be around 1/4" i.d. - this is an estimate since I did not pull them off the tank.

If I run the tanks down to around 1 gallon or so left, and fill up using your average gas station's 1" hose, will I fill the top tank, close the cover and drive off only to have the top tank drain down into the bottom tank leaving the top tank only half or 3/4 full?

I've not run the tanks much below 3 blocks on the gas gauge, but so far, this has not happened at fillups. Is there a bigger hose that I did not see that connects both tanks?
 

Blrfl

Natural Rider Enhancement
Joined
Aug 24, 2005
Messages
5,689
Age
55
Location
Northern Virginia
Bike
Fast Blue One
STOC #
4837
The three small hoses on the upper tank are a breather and air vent which don't carry fuel and an overflow drain which does only when the tank is overfilled.

The two tanks are joined by a larger hose at the rear of the upper tank, which you can see if you look underneath it in front of the seat bracket. If the hose isn't clogged or kinked, there's no way to fill the upper tank without the lower tank being full.

--Mark
 
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