Reserve capacity

[throb]

How much fuel is typically left in Connie's tank when the main supply is all used up?

[DeansZG]

Approximately 1.5 gallons....  I'm guessing your fuel gauge is optimistic & has not had the usual "fix" applied to it yet? 
Fix#1; remove seat, remove tank, remove sending unit, bend float arm, re-assemble, fill with gas, ride until you need to flip on reserve, see if fuel gauge reads correctly, if it does, great, if not repeat procedure all over again.....
Fix#2;  go to your favorite electrical hooby shop & pick up a 1/4 watt 250 ohm resisitor... remove seat, locate electrical connector for sending unit, use the resistor to jump the two wires from the sending unit at the connector, seal it up with electrical tape, re-assemble & you're good to go.....you'll find that the bike will need to switch to reserve when the fuel gauge nears the halfway mark in the red zone....
Good Luck

[Outback_Jon]

pick up a 1/4 watt 250 ohm resistor...

I thought it was a 220 ohm resistor.

[throb]

Actually I did the mechanical adjustment way yesterday, but rode until reserve, and after pulling the sending unit, I plugged it back in and made the appropriate adjustments to get the needle where I wanted, then buttoned it all up.  The only reason I ask reserve capacity is because I had to switch to reserve from a topped off tank after only a little over 200 miles and thought I was getting cruddy mpg, thinking reserve was less than a gallon. 

[T Cro ®]

Actually I did the mechanical adjustment way yesterday, but rode until reserve, and after pulling the sending unit, I plugged it back in and made the appropriate adjustments to get the needle where I wanted, then buttoned it all up.  The only reason I ask reserve capacity is because I had to switch to reserve from a topped off tank after only a little over 200 miles and thought I was getting cruddy mpg, thinking reserve was less than a gallon.

Yes reserve is roughly 1.5 gal....

[oldsmoboat]

When I bought mine used, the owner had already done the resistor fix.
I have to go to reserve when the needle hit the white line at the end of the main tank.  It wont get into the red without cutting out.

[RapidRoy]

One other slight variation I read about before the server crash was to insert a variable resistor rather than a fixed one. Once you hit reserve, adjust the variable resistor to place the gas gage needle to where you want it ( in the red, just prior to the red...). Then measure the resistance to determine the exact value required.

I don't remember what the original poster did once they knew the exact value, because you can't purchase resistors that are exact values. I image you could do any one of the following:

1) Leave in the variable resistor, making it more permanent.

2) Pick the closest common resistance value. In this case your needle probably won't be exactly where you want it, but it should be pretty close. The value I've see thrown around has been 220 Ohms. Resistors are commonly available in 200, 220, 240, 270 (+/- 5%).

3) Use multiple fixed resistors to create a value closer to the exact value needed. That is, put resistors in parallel and series to create a custom value. For two resistors in series, the combined value (Rc) is simply Rc = R1 + R2. For parallel combinations Rc = (R1xR2)/(R1+R2). A parallel combination of 360 and 1000 Ohms would become (360x1000)/(360+1000)=265.

One note on the variable resistance method. Before connecting and adjusting the variable resistor, make sure you set it high. If you don't, you'll be creating a short. For example, if using a 500 Ohm variable resistor, set it to 500 Ohms prior to hooking it up.

[Uglydog56]

I wacked 1/2" off the tube and my bike fills up about 6.2-6.5 when it hits reserve now.  That still leaves me about a gallon of reserve.

[T Cro ®]

I wacked 1/2" off the tube and my bike fills up about 6.2-6.5 when it hits reserve now.  That still leaves me about a gallon of reserve.

Same here... Think I ended up cutting off 5/8" with roughly the same results.

[Bergmenized]

Concours on center stand, tank completely dry.

1) 40 ounces, 1.25 quarts, .31 gallons up to bottom of reserve (unuseable fuel).
2) 187 ounces, 5.84 quarts, 1.46 gallons reserve capacity.
3) 736 ounces, 23 quarts, 5.75 gallons main capacity.

Total fuel capacity = 7.52 gallons.
Useable fuel capacity = 7.21 gallons.

Dan