R1100S motronic interchangable? Poor fuel mileage issue.

[njsax]

Originally Posted by Pete.

... I've got 208 miles from 24.8L of fuel which is 8.4miles/litre or 38.2 MPG. Usually I can comfortably manage 9.4miles/litre or 42.7MPG which would give a range of 235miles or thereabouts and I could stretch that to just about 250mles if I rode very frugally.

Pete, are you sure you're not measuring kilometers instead of miles? Here in the US, I'm lucky to get 170 miles out of a tank of gas. Even if you ride like an old lady I don't see how you could possibly get 40% better cruising range than me. What's up with that?

Hold on .... I just found this ...
What bike are you riding? You say that you used 24.8L of fuel. According to the BMW Rider's Manual, max fuel capacity is only 18 L, which accounts for your extra 40% range.

[Pete.]

John, it's a R1100S. I have no ABS pump so I re-mounted the motronic unit to lay flat and then cut the bottom out of the tank and welded in a section to use up that space. It gives a total capacity of 25.8L, filled to the very brim.

[njsax]

I see. Well, that explains it. These bikes can certainly use more fuel capacity.

[tomvv11]

Many of us aspire to your tank capacity.

[arbezc]

Hi Pete,
I noticed your mention of a 25 litre tank on an R1100S. Is it customized or aftermarket? Could you provide the make & source?
I expanded mine to 24 litres using old parts. The side panels had to be cut on either side. Also the fuel level sensor is in its original position, it now triggers the fuel light too early.
Thanks, Charles

[arbezc]

Sorry Pete, I responded to an older link without your tank description. Nice work.
I decided to keep the ABS unit. The tank is expanded on both sides but below the fuel level sensor. Your expansion appears to be above the sender, does your light trigger properly?
I like the added capacity on long rides - it matches my bladder capacity. When the ABS goes I'll follow your approach.