Secondary fuel tank/fuel fill ups at 1 fuel bar

I recently had my company car go into the shop, so I decided to commute wit my ST instead of my Suburban. My usual habit is to top off my off my fuel once I get around 200 miles or so on the odometer, and/or when I get close to home after the ride. Since I was commuting and have an infantesimle number of gas stations near work, on my way home, and near my house (13 mile commute each way) I figured I could run it down yo the flashing last bar before I gassed up. I did this twice. 1st time I got to around 260 miles before it started flashing, so I topped off with 5.4 gallons. . Which seemed odd since the ST holds 7.7. That tank only lasted 187 miles before I got the flashing bar?? The answer is that when I topped off the 1st time, I did not give the secondary tank time to back fill. This last top off, I realized my tank gurgling and bubbles in the tank. Then I realized that since I went to the flashing gas bar the secondary tank had been partially emptied. I just wanted to post this to help people not to stress over seemingly less miles after filling up from an almost empty tank(like i was syarting to do). The obvious solution is to top off the main tank and let it fill the lower tank, and then finish topping off the portion that filled the secondary tank. . . .

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Thanks!
This is a great tip.


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If your having to wait for the fuel to slowly go into the lower tank, you may have a problem with a pinched or obstructed fuel joint hose.
I've never seen an ST1300 upper fuel cell take any amount of time to transfer the fuel from one tank to the other.
The gurgling your hearing, I assume, after riding the bike, may be related to heat on the rear cylinders heating up the fuel.

I asked a similar question - about the speed with which gas will flow into the lower tank. I was told that you cannot fill the upper tank at a gas station so fast that fuel will still be flowing down when you reach the full mark. Now if you get one of those speed fill tanks they use in formula 1 racing, all bets are off.

Igofar said:

If your having to wait for the fuel to slowly go into the lower tank, you may have a problem with a pinched or obstructed fuel joint hose.
I've never seen an ST1300 upper fuel cell take any amount of time to transfer the fuel from one tank to the other.
The gurgling your hearing, I assume, after riding the bike, may be related to heat on the rear cylinders heating up the fuel.

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I'll have to lift my tank and look at the hoses. It had nothing to do with heat, I had only risen it for less than half a mile and as the bibles came up, the fuel level lowered, and not through the overflow.

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Hueyf4i said:

I'll have to lift my tank and look at the hoses.

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Before you raise it, remove the seat and take a peek underneath the aft edge of the tank and see if the hose is kinked.

--Mark

I spoke too soon. I took up the suggestions and peeked under my tank from behind and saw that the smaller hose was sandwiched between the frame and the tank. I was able to gently push it free. I'll have to make sure I double check it's position for now on when I lift the tank. Thanks to all.

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DavidR8 said:

Thanks!
This is a great tip.


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Click to expand...

Guess I was too hasty with my assumption that the secondary tank bank filling was wrong. I checked out the suggestions from the senior ST owners and found that I had pinched my smaller fuel line between my frame and tank.

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We're here to help :call:
Glad you found it was a simple thing to fix.
Now get out there and ride safe and have fun.
Igofar