Electronics I need help brain storming

Help! I'm looking for ideas. I'm designing an auxiliary motorcycle gas tank for more capacity, this tank will have an electric fuel pump to fill the other tank when it is almost emty, I'm trying to figure out how to run the pump just long enough to empty into the other tank and not over run the pump to the point it runs dry and burns-out the pump. I'm thinking flip a switch to a relay-delay, the bike does have a low fuel light in the speedometer...Any ideas???
-Franklin

 

Sounds to me like a couple of float switches are in order.

When the float in the upper tank falls, the pump turns on until the float in the lower tank falls.

 

( Miser ) The tank that I'm designing is the upper tank, so do you think that maybe a float switch in that tank would do the trick? And where could I get a float switch?
-Franklin

 

Wait a sec, let me get this straight. The auxilliary tank is going to be ABOVE the standard tank?

 

yes and I would like to keep the install as simple as possible, I plan on marketing these tanks

 

This tank is for the haley v-rod and the stock gas tank is mounted under the seat.

 

If the aux tank is above the main tank, then you could use a small pump to get it started, but from there, it should just siphon down to the main tank, use a small ball valve to control that.

 

Well, it seems to me you could let gravity do the work of transferring the fuel. A simple float valve in the lower tank would keep it from overfilling.

Edit-
#7: You wouldn't even need a pump at all, just have the fuel outlet at the bottom of the auxilliary tank. Also, a float valve would make the whole thing automatic, without the need for a ball valve.

 

I like that idea and yes gravity will work but my concern with a float vavle is if it sticks open the lower tank would over flow.