Probably more than I let on! I wasn't aware that fuel injected bikes didn't have a reserve mechanism though. I would have thought that would make sense. Fuel injection is another method of fuel delivery so why would it seem so daft not to expect it to have reserve?!?

That aside....

I'm presuming most EFI bikes have a warning light at least. So with this in mind you must know roughly what milage you get when the fuel warning is given, either by switching the petcock on a carb'ed bike or seeing the light on an EFI machine, and from there you know roughly how far you can go when the bike finally runs out.

The principle is the same no matter whether it's a petcock or an idiot light.

 

Fuel gauge on my "toaster" dash on my '91 FLHS Electra Glide Sport is surprisingly accurate. With regular speed riding and shifting I can expect 180 miles per 5 gal. tank without going to reserve. A combination of the gauge plus the tripometer leaves no excuse for running out of gas ( other than a personal competition to see if I can "make it home" on what's left in the tank).

Old style fuel petcock valves like mine are manual and the "reserve" function is simply a lower feed hole in the petcock standpipe inside the tank that sucks all the way to the bottom. On reserve I've got about 12 miles if I nurse it.

Newer bikes went to vacuum petcocks then electrical with the FI bikes making a reserve feature difficult to engineer and expensive for the MoCo I'm guessing since you could no longer turn the spigot with your finger.

Maybe another reason for not having a reserve feature on on FI bikes is that it's not good to let that fuel pump and those injectors run dry. Would probably happen more with the "reserve" feature if present. Maybe that would cause pump and injector damage and confuse the black box too?

Have noticed on my 80" Evo ( top end, cam, S&S carb, etc.) that if I'm running over 80 mph my mileage drops from around 40-42 mpg to about 30 mpg. I rarely ride like that anymore for long sustained periods though but when I do have to keep an eye on that sinking fuel gauge.

 

What kind of answer is this?
The guy asked a legitimate question, and was pretty clear explaining that he did not know why there is no reserve on the FI bikes. The fact is, there is no reason not to have reserve on FI bikes.

 

BMW were the first to fit FI on production bikes (Munch had them much earlier, when they were mechanical not electronic) and their FI bikes didn't have a reserve tap, in fact I don't believe they had a tap. That is probably to prevent the dumb operator forgetting to turn the tap on and hence save the pressurised fuel system from unnecessary distress.

By contrast most modern carbs use a gravity-fed float and needle regulating system that may suffer leakage, hence an on-off tap is a wise precaution. It also does not present the fuel system with any significant problems if left switched off while running the engine.