I have a few questions!

[frogslinger]

Originally Posted by CManT1914

What is the point of the fourth one? I'm not understanding what it's there for. It comes on when the low fuel light comes on?

Exactly... on my bike when it drops below .9 gallons the low fuel light comes on... assuming I am getting 30 miles to the gallon then I can go 27 miles. Now suppose for a minute I am taking Inspiron's advice and am completly ignoring all my gauges and do not look down for 15 mins... how do i know how long my low fuel light has been on?... well in my case Yamaha was kind enough to include a 4th odometer, which the gauge cluster automatically resets and switches to, that way even the greatest of Zen riders will know how far they have riden since the low fuel light came on... the gauge cluster reads F: 17.2 .... or however many miles it was since the light came on.

[frogslinger]

Originally Posted by Rickster

I've never seen the type of resarve that you describe. The ones I have had apart have a brass tube that extends up into the tank about a inch or so that the gas flows through when the lever is set on main. When the level of the gas drops below the opening in the top of that tube, the motor runs out of gas. when you flip the lever to reserve, it bypasses that tube, and draws gas from the bottom of the tank. There is a small rubber hose running under the backbone of the frame connecting what you call the ears so both sides drain down together. I'm not saying what you described is wrong, I'm just saying I've never seen it.

It's never a good idea to let your FI bikes run out of gas. It's hard on fuel pumps, and the FI system itself.

I will be honest... i have never torn apart a fuel tank, so I am just going off of what I have been briefed and/or read. I belive the setup you described is what was on my RM125, but I am not sure. What I described is what I am told (by vast swarms of shade tree mechanics) was used on most cruisers until fairly recently...

[inspiron]

FWIW, most "normal" bikes only have one tank. There are two fuel pickups, one slightly above the bottom of the tank, and a second one at the bottom. The upper one, used when the petcock is set to "normal", has two advantages:
1) the crud in the tank settles to the bottom, so there is less chance of sucking crud into the engine/fuel filter when the pickup is not at the bottom, and
2) you can switch to "reserve" when it starts to sputter, knowing that you best start looking for a filling station.

Most fuel-injected bikes don't have a petcock, and therefore need better fuel filters (a single pickup, at the bottom of the tank). Since most bikes don't have a fuel gauge, the only clue a rider has is to estimate how far he can go on a full tank, and look for a gas station before he runs out of gas. The "idiot" light will come on when there is about 1 gallon in the tank - this replaces the need to reach down and switch to the reserve pickup.

Since there is a sensor in the tank (for the idiot light), I see no reason that the bike couldn't have a fuel gauge. (My GSX has one). It is purely a cost-savings issue from the manufacturer - that's why only the "high-end" bikes have one.

BTW, frogslinger, I didn't say that I never look at my instruments ... I look at them quite often (speeding tickets are incredibly expensive in Switzerland), but I don't look at them when I'm concentrating on getting across a busy intersection or accelerating hard to get out of danger or passing a white-haired sunday driver. That's why I don't think a shift light would be of any help to me. YMMV.