Most economical fast bike?

Another trick is rear sprocket size... Now I had a 46 tooth sprocket which ment at 90mph I was doing 6500 rpm in 6th gear. Now my 45 tooth means that at 90mph I'm now doing 6700-6800 rpm in 6th. So by the same reasoning if you went for a 47 tooth rear 90mph should be 6300 rpm. Not a massive difference but should increase your mpg if you spend alot of time at high speeds and on motorways. I was getting about 50-55 mpg out of SV with the 46 tooth sprocket so it might even push it up to 60.

Engine revs isn't everything though. Doing 30mph in 6th uses more fuel than 2nd. You want to have the engine revving in its most fuel efficient zone. And dropping your speed 10mph will give you the biggest mpg increase!

[Stu]

I've heard that, but when in a car with a MPG gauge the consumtion always fell if I went into a higher gear.
I doubt it would be more economical in 2nd.

[dirtydog]

Originally Posted by fizzwheel

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You can do a lot to improve fuel economy, ride a bit slower

Fizz did you not see who asked the question?

Revs tell you how fast the engine is turning over
Right hand tells you how much fuel is going in to the engine

30mph takes probably around 3-5hp whether in 1st or 6th gear.

In 2nd/3rd gear the engine will be running near is optimum rev range. I.e. most efficient, Throttle will barely be on.
In 6th gear the engine will be very low in the rev range, way out of its efficient rev range. Try putting the throttle on? engine will be likely stutter. The throttle is likely to be on more than if you were in 3rd gear.

Cars go by the same rules, but as the powerband is so much smaller its not as noticeable. Besides, those things aren't at all accurate P

my sv was great 130 to the tank. Cbr was not so good though 100-110 if I was really lucky. Mind you 14k in 2nd everywhere doesn't do much for the economy...

The zx-6r will give about 50mpg (I'm told). I'll let you know after I've been on it for a week.

my new car is my new toy for MPG i'm always looking at the fuel computer trying to get the best mpg. down hill in 5th on 900 rpm tickover it says 199mpg.

[Biker Biggles]

There's a tad of confusion between most efficient rev range and most economical running.The two are not quite the same as fuel consumption is affected by other variables.So for example you may be doing 90 MPH in 4 th gear and the engine is within its most efficient range,but if you do 55 MPH in top gear the engine will not be in the correct rev range but will use far less fuel.The "forgotten" variable here is wind resistance which rises exponentially with speed.The other factor is that the engine will be producing more horsepower if it is running in the efficient range,but less power is actually needed to maintain that given speed so the efficiency is wasted.There used to be a saying that doing "thrifty fifty"in top gear was the best compromise.

But pretty boring.

i was always made to believe it was 62mph in top gear for max fuel economy, reading car books and the like.

Originally Posted by Biker Biggles

There's a tad of confusion between most efficient rev range and most economical running.The two are not quite the same as fuel consumption is affected by other variables.So for example you may be doing 90 MPH in 4 th gear and the engine is within its most efficient range,but if you do 55 MPH in top gear the engine will not be in the correct rev range but will use far less fuel.The "forgotten" variable here is wind resistance which rises exponentially with speed.The other factor is that the engine will be producing more horsepower if it is running in the efficient range,but less power is actually needed to maintain that given speed so the efficiency is wasted.There used to be a saying that doing "thrifty fifty"in top gear was the best compromise.

But pretty boring.

Yeah, not quite the same, but a closer approximation than using the rev counter. The right hand rule is best!
If you want best mpg?
walk