RE: 1200 vs 1250 Fuel Consumption - 2

Zitat von Goon im Beitrag #15

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Any idea what the gearing is on these bikes, what would be the rpm at 70 mph, compared to my Suzuki Gsxs1000 which is 4500rpm?

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On my previous 1200 hexheads, I never used anything else than 87 gas even thou the recommended was 89. What always killed my fuel consumption was gas with ethanol or so called “winter gas” here in Canada, it’s lighter and has less calorific value.
On different note, I did read somewhere that 87 has actually higher calorific value and is more pure because of all the octane additives in 91, so it should have better mileage.

Since 2005 every R1200 bike I owned has been run on Shell super unleaded ( 97/98/octane?) rather than the 95 'they could use'
The R1200ST had knock sensors to allow either fuel but 'better performance' on 97octane or above.
Since then, All bmw R1200's the 2005 ST was 55/57 mpg, dropping to 52/55 in winter over 40k and 17years ownership
The 2007 S and 2013 R models were around 55/60 although the R was nearer to 65 across europe, including many 80kph/50mph miles across Norway
Both the 2015 RS 'first version' and the later updated 2017 RS give me 63/65mpg local use (never less than 25 miles any trip and no town/shopping pick-ups)
Satnav 1000 miles service to service one year of covid 2021 to 2022 gave 67 mpg
Again Denmark/Norway/Sweden exceded 70 mpg over a few days meandering about with "nowhere to go and all day to do it."
I know motorcyclenews last year showed that the extra cost of super unleaded was repaid by identical or better performance, mpg without guessing if 5% 10 % watering down was worth the gamble., certainly not for me. Gettting better mpg = the extra cost so buy the better fuel!
Each similar model engine over 18 years has been improved slightly, sometimes small updates, but they do seem to add up.
I guess as emission controls keep being tightened, fuels improvements, engineering tolerances improve with water cooling, leaner running, better oils, shift cams etc.
I would expect the R1250, in identical uses to again be better again on fuel due to these improvements and tyre technology (although tyres are retro fitted as we all take the latest advertising bait)

Zitat von Luma46 im Beitrag #18

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On my previous 1200 hexheads, I never used anything else than 87 gas even thou the recommended was 89. What always killed my fuel consumption was gas with ethanol or so called “winter gas” here in Canada, it’s lighter and has less calorific value.
On different note, I did read somewhere that 87 has actually higher calorific value and is more pure because of all the octane additives in 91, so it should have better mileage.

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The gas in Canada is 87, 89 and premium 91 octane number (whatever it is). There might be higher number gas in some big cities, but haven’t seen such a station in Atlantic Canada. Pretty much all cars run on 87 and and a good part of motorcycles, my 2020 CB500X has recommended 87.
Trouble with 91 premium gas here is that most, if not all stations, have only one hose/nozzle for all three octane products. Because at least 90% fillups are 87 gas, there is a high chance that first few liters that I put in my tank will be 87 even if I select 91.

Zitat von Luma46 im Beitrag #22

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The gas in Canada is 87, 89 and premium 91 octane number (whatever it is). There might be higher number gas in some big cities, but haven’t seen such a station in Atlantic Canada. Pretty much all cars run on 87 and and a good part of motorcycles, my 2020 CB500X has recommended 87.
Trouble with 91 premium gas here is that most, if not all stations, have only one hose/nozzle for all three octane products. Because at least 90% fillups are 87 gas, there is a high chance that first few liters that I put in my tank will be 87 even if I select 91.

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Zitat von Luma46 im Beitrag #22

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The gas in Canada is 87, 89 and premium 91 octane number (whatever it is). There might be higher number gas in some big cities, but haven’t seen such a station in Atlantic Canada. Pretty much all cars run on 87 and and a good part of motorcycles, my 2020 CB500X has recommended 87.
Trouble with 91 premium gas here is that most, if not all stations, have only one hose/nozzle for all three octane products. Because at least 90% fillups are 87 gas, there is a high chance that first few liters that I put in my tank will be 87 even if I select 91.

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Zitat von Luma46 im Beitrag #22

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The gas in Canada is 87, 89 and premium 91 octane number (whatever it is). There might be higher number gas in some big cities, but haven’t seen such a station in Atlantic Canada. Pretty much all cars run on 87 and and a good part of motorcycles, my 2020 CB500X has recommended 87.
Trouble with 91 premium gas here is that most, if not all stations, have only one hose/nozzle for all three octane products. Because at least 90% fillups are 87 gas, there is a high chance that first few liters that I put in my tank will be 87 even if I select 91.

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Zitat von Richard230 im Beitrag #24

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Zitat von Luma46 im Beitrag #22

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The gas in Canada is 87, 89 and premium 91 octane number (whatever it is). There might be higher number gas in some big cities, but haven’t seen such a station in Atlantic Canada. Pretty much all cars run on 87 and and a good part of motorcycles, my 2020 CB500X has recommended 87.
Trouble with 91 premium gas here is that most, if not all stations, have only one hose/nozzle for all three octane products. Because at least 90% fillups are 87 gas, there is a high chance that first few liters that I put in my tank will be 87 even if I select 91.

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It is the same in California. I usually fill up with 91 E10, but the other day I gave the recommended 89 AKI a try. My R1200RS ran OK, but it did seem to vibrate more than usual. Most of the time it is very smooth and I don't notice any vibration. But this time I did. I think I will return to 91 octane and see if the vibration level improves.

I might add that I typically get 50 miles per gallon when ridden easily.

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So, if we use the 1.8L estimate from Paul, I usually fill-up after 200 miles and need ~4-gallons (15.3L). So, if 1.8L is 87 AKI and 13.5L is 89 AKI, my mixed AKI should be 88.8 AKI. I think I'm OK, relative to this issue.

The owner manual for 1200rs says recommended 89 AKI, alternative 87 AKI, so I have no issue with 87. I don’t think I am gaining much, if anything, with 91, but I know that I am losing some 10% fuel consumption with either ethanol or “winter gas” which is here usually from mid October till mid April. Same with my car.

Several thousand miles later, and still running premium (93 octane), I consistently see better performance, especially in mid to high revs- just better power delivery when compared to running regular (87).

Fuel economy (mpg) remains steady at 10% better with premium. I easily added 20 mi/tank.

I reconfirm this periodically when I’m somewhere without premium and have to fill with regular. Yes, the ECU compensates, but I can feel it. And the extra regular left in the tube pisses me off too lol

At a track day last year, I accidentally (and $tupidly) put high octane (98 or 102, I forget) race fuel, no ethanol, in for the second day. While the track is hardly the place for fuel economy studies, I can say I could not tell any difference. Hence, my unscientific conclusion is low 90’s is enough.