The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: 2dogs1cat on January 11, 2013, 08:33:00 PM
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'79 R65, now has 20,044 km on the odometer.
I was going through my trip log book tonight and became curious about fuel consumption.
I rode 656 km, used 29.7 L of gas = 4.5 L/100km or 62 miles to the gallon.
Would that be considered middle of the road fuel consumption?
:^)
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I think the best I have gotten is about 52 mpg on long trips and the worst about 43 when it was all around town with lots of idling so 62 would be great mileage.
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Is that an Imperial gallon ?
I converted your metric units to US and came up with 52 statute miles per US gallon .
That's doing quite well, the only time I could come close to that, was when the speed limits were 55 mph and no alcohol in the fuel .
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Hello !
4.5 liter per hundred kilometer is quite good as it is the stated BMW consumption when bike was new (as per the user manual) ... These figures are as hard to get in normal use as hen's teeth....
I was able to get them once in Ireland when we mused around small roads at very low pace a long time ago.
So I think either your bike is perfectly tuned and you're gentle with the throttle or you mis calculated something...
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62 MPG Imp is close to what it should do according to BMW's own figures for the DIN standard test which is 61.4 MPG.
From the reports we get I would have thought that figure is very good and towards the top end of what's achievable for an R65.
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Hello !
4.5 liter per hundred kilometer is quite good as it is the stated BMW consumption when bike was new (as per the user manual) ... These figures are as hard to get in normal use as hen's teeth....
I was able to get them once in Ireland when we mused around small roads at very low pace a long time ago.
So I think either your bike is perfectly tuned and you're gentle with the throttle or you mis calculated something...
I'm a slow rider = 100 kph, 62 mph
;)
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I don't doubt 62 MPG Imp at all. It's what the bike should do. I can hit that figure with ease even ridden fairly hard. And although I've got the smaller engine it's still hauling around exactly the same weight with the same aerodynamic drag and the same transmission losses. When I trundle down county lanes in the summer I can get 70 - 75 MPG. but only if I tune the carbs right which in this case means idle mixture.
The thing about CV carbs is that in this sort of use and even when cruising up to legal speeds you are only using 1/8 to 1/4 throttle so the idle mixture circuit is still having a significant impact. You don't get good mileage with excessively weak mixture across the range but you don't get it with excessively rich idle mixture either. The mixture screws are very sensitive so adjustments need to be made in very small increments. For this reason I don't agree with the set it right than "open up by an 1/8 or 1/4 turn" philosophy. With our mixture screws only open 1/2 a turn in the first place those are huge changes. I just set them right which means as weak as the engine will tolerate and still have good clean pickup. Basically the Bing Manual method.
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I just filled up yesterday, got 35 (U.S.) mpg .... just about as high as I get.
I suspect I'm running a bit rich, but haven't bothered to start troubleshooting. I also know that 2dogs1cat and I have extremely different riding styles.. Being in Texas, it's every man for himself out there.
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With 10% alcohol in the fuel and 65-75 mph speed limits here , my mileage has dropped to around 39-40 .
My '91 CRX does better !!!!!!!!!!! ;D ;D ;D ;D ;D ;D
Usually around 195-200 miles to reserve .