Fuel reserve

[timminator]

I was riding today, and got dangerously close to running out of fuel (I thought).  The station I had planned to stop at was out of fuel so I had to ride a lot further than I planned.  The fuel light came on, and the estimated miles left was down to 4 miles when I finally filled up.  To my surprise, when I filled, it only took 5.785 gallons.  And I got it completely full, it was touching the bottom of the filler neck.
According to the owners manual:
Usable fuel quantity Approx. 6.6 gal (Approx. 25 l)
Reserve fuel quantity Approx. 1.1 gal (Approx. 4 l)
I guess I don't understand when the "reserve" kicks in.  Was I using that last 1.1 gallons once the fuel light came on, or does the reserve start being used once the estimated miles left gets down to zero?  Based on the amount of fuel I put in, I would guess that I would have had a full gallon left once the miles-to-empty reached zero.  Does that sound right?

[David.]

Based on the amount of fuel I put in, I would guess that I would have had a full gallon left once the miles-to-empty reached zero. Does that sound right?

From my experience with a TC, I would say yes, have run mine until the range (miles) is zero, then brimmed the tank & it's had 3 to 4 l left, (based on a 27 l capacity).

For some reason, I've always thought the TC had a 27 l fuel tank, but like the LC, the usable fuel capacity is 25 l, with a reserve of 4 l, does this mean the tank capacity is actually 29 l or 25 l.

If the tank capacity is 25 l, then obviously I'd only have 1 to 2 l left!

The Rider's Manual says, "the range readout indicates how far you can ride with the fuel remaining in the tank."

Also, when the "fuel down to reserve" warning shows, you've hit reserve, approx. 4 l.

Based on this info., when the range shows zero, there shouldn't be any fuel left in the tank.

[guest2360]

Some time ago I arrived at South Minns Services with my guage showing 2 miles left only to find they were out of fuel.  The next place I saw a Services sign was Dunstable 27 miles on.  Can't  remember what it took I was just relieved to get some. So I also suspect that when you show no fuel left you really have 4l.

[Our Gee]

To put another slant on this. our "Hexhead" suddenly stopped with about a third of a tank full showing on the gauge. I immediately suspected a duff Fuel Pump Controller having had previous experience of this annoying problem. I actually started to remove the fairing panels at the roadside to fit my Controller Bypass Wigit when my better half suggested we push the bike to a nearby petrol station and see if indeed we where out of fuel. (Esso staion on Low Lane, DaygloDavid will know the one.) A couple of quids worth in the tank and hey presto, away we went. So now I don't rely on the gauge only, but also keep a rough check on mileage since my last fill.

[T6pilot]

I always reset #1 trip meter at each fueling, bike gets 42-50 MPG US depending on my riding style. At the 200 mile point, i'am looking for fuel,besides after 3-4 hours need to stretch. gone 250 before and still could only get 5.6 gallons in tank

[timminator]

I always reset #1 trip meter at each fueling, bike gets 42-50 MPG US depending on my riding style. At the 200 mile point, i'am looking for fuel,besides after 3-4 hours need to stretch. gone 250 before and still could only get 5.6 gallons in tank

Thanks for the responses...I normally never let it get below 2 ticks myself, my question was more just out of curiosity about how the reserve works.  Based on my experience and what I'm hearing here, I think the reserve remains untapped until the dashboard range equals 0.  I'm not going to test that anytime soon, but good to know.

[David.]

Whilst having my TC serviced today, I asked the dealers about the tank capacity etc.

I was told that the tank capacity is 25 l including the 4 l reserve & that when the range is zero, there is no fuel left.
From what's been posted so far, it would seem that there is fuel left in the tank when the range hits zero.

When the low fuel warning light comes on, the range shows approx. 45 - 50 miles which I would expect to get out of around 4 l.

Next time I run the bike to zero range, I'll confirm how much I put in & take that away from 25 l to see what if anything is left in the tank.

[guest2360]

Just shows how knowledgeable some dealers are.  They just read the manuals.

[timminator]

Correction - Found this in my riders manual, seems to contradict what I said earlier: 



The "usable fuel quantity" indicated in the Technical data is the fuel quantity, which can
be re-fueled, if the fuel tank was completely emptied, i.e., if the engine dies off due to
lack of fuel.


Usable fuel quantity
Approx. 6.6 gal (Approx. 25 l)
Reserve fuel quantity
Approx. 1.1 gal (Approx. 4 l)


So, when the warning light comes on, you are using the reserve.  What might be inaccurate is the range calculation, which is obviously just an estimate. My range was indicating 4 miles left, and I still had almost a gallon of fuel left in the tank (Added 5.785 gallons to 6.6 gallon tank)

[David.]

The "usable fuel quantity" indicated in the Technical data is the fuel quantity, which can be re-fueled, if the fuel tank was completely emptied, i.e., if the engine dies off due to lack of fuel.

Sounds like the dealer was correct & the fuel tank capacity on my TC is 25 l, same as the LC's.

[guest2360]

25l might be the total capacity of the tank but I can't believe the low fuel light and range count down start when there is only 4l left.  No way would BMW leave themselves open to multiple recovery requests from stranded riders who's gauges were showing a couple of miles left.  It's the same with speedometers, they are always a bit over.

[David.]

"The proof of the pudding is", run the bike until the range shows zero, then fill up at the earliest opportunity & subtract the amount of fuel added from 25 l.

The examples posted so far, clearly show that there if fuel left in the tank when the range hits zero.

[timminator]

25l might be the total capacity of the tank but I can't believe the low fuel light and range count down start when there is only 4l left.  No way would BMW leave themselves open to multiple recovery requests from stranded riders who's gauges were showing a couple of miles left.  It's the same with speedometers, they are always a bit over.

I think you hit the nail on the head.  BMW does not want the recovery requests, and they also know how bad it is to run your bike out of fuel.  Seems like the reserve light comes on when there's closer to 2 gal (7.5l) left in the tank.  Not a bad strategy on their part, but I would rather know where I really stand.

[futterweasel]

I think you hit the nail on the head.  BMW does not want the recovery requests, and they also know how bad it is to run your bike out of fuel.  Seems like the reserve light comes on when there's closer to 2 gal (7.5l) left in the tank.  Not a bad strategy on their part, but I would rather know where I really stand.

Whats so bad about running out of fuel, does it damage the bike in some way? I got down to one mile left on the range gage last week in Scotland after the satnav sent me to a none existing garage.

[guest2360]

And how far did you manage to ride with an (empty) tank before you found some.