Fuel tank function, capacity, mileage questions.

The other day, I ran out of gas on my 750. Basically it was completely my fault. I had forgotten that the day before I had switched it to reserve when I was messing with everything and forgot to switch it back. Luckily, I was only 4 blocks away from a gas station, and most of it was down hill. So I coasted down hill for about 2 blocks through an alley and only had to push another 2.

Though my fuel light never came on, so I assumed it didn't work.

That was this past Friday (6/4/10).

Today (6/8/10) when I pulled my bike out of the garage this morning to start her up and let her get warm while I put my gear on, sitting on the side stand, the low fuel light came on. Of course when I stood it up, the light went out. I planned to stop a little less than half way through my 30 mile commute for gas.

About a mile from the gas station, as I approached a traffic light, it stalled out. The Fuel light never came on. I switched to reserve and she started right up. I got to the station and filled up.

These events, bring up a few questions.

1. Should the FUEL light turn on when the regular capacity is low, or when reserve gets really low?

2. Roughly how much gas is left when I switch to reserve? (Stock 82 750 LTDH3 tank) When I filled up, I put in about 2.5gallons, but filling it on the side stand doesn't allow me to fill it completely to the top, so I can't really calculate it based on stock capacity.

3. For those of you that actually run the tank down, is that how you know when to switch to reserve, when it stalls out? It was running perfect up to that point, so I had no warning.

4. I believe I am getting roughly 100 miles to a tank. Does that sound right? (stock intake, exhaust and jetting AFAIK).

The fuel tank & fuel gauge on my 81 KZ650-CSR are probably virtually identical to yours. The low fuel warning lite starts to glow before I have to switch to RES. I continue riding the motorcycle a while after the warning lite glows steady, but I don't recall how many miles I can go before the bike starts to stumble from lack of fuel. After switching to RES, I believe I can go about 20 miles, then I have to find a fuel station real quick like.

The fuel tank holds ~3.3 gals.
RES uses the remaining 0.5 gals (so the 20 RES miles is fairly accurate since the bike typically gets ~42-45 mpg around town).

If you run out of fuel, there may be some left on the side opposite of the petcock. The frame tube hump causes about a litre of fuel to be trapped over there. Tip the bike over, or lift the tank and tip the fuel to the petcock side.

Galactica wrote:

If you run out of fuel, there may be some left on the side opposite of the petcock. The frame tube hump causes about a litre of fuel to be trapped over there. Tip the bike over, or lift the tank and tip the fuel to the petcock side.

Excellent advice. I've never thought of that, but it makes perfect sense.