Sprocket change, chain too short? WTH?

[faffi]

A 33% reduction in consumption doesn't seem realistic on average. If you can get a 10% improvement, you should count yourself lucky.

[markstertt]

Is it safe to assume that a good gps will be as accurate or more than any calculating I might attempt (lazy)? IF so I think I'll get one just for fun. My buddy and I just took a 3 day ride up the coast and with my 17/44 sprockets came back with 643 miles and my buddies BMW F800GS indicated 653 miles. Indicating 65 mph typically (no good wind protection) we were still being passed so I know I wasn't doing an actual 75-80 mph. I refueled at 160-170 miles with 1 bar but never got to the point it was blinking, ended using 10.391 gals, I calculated each fuel up and got a worse of 58 mpg and best of 65.4 mpg...using my buddies total miles gave me about 1 mpg better. Maybe I'll try a smaller rear sprocket for the next trip but for all around I kind of like this combo.
 
 
 Bikes dash gave average of 63.8 mpg for trip total so would seem to be pretty close with this gearing and the miles it thinks we covered.

[level41]

The readout of 1.5 gal is approx. And I definitely rode it harder with the old sprocket.
I'm just trying to take it easy on this chain, since it's brand new, and still stretching.
 
Still, on the old sprocket, I would be doing 4,5-5.5k RPM, which is where the bike is tuned the leanest (resulting in the cleanest exhaust, but at the cost of lower MPG and power).
On the new one, I'm going 4-4.5k RPM, which aside from the lower RPM, is where the bike is closer to the stoic mixture, resulting in much better MPG.
On average your MPG gain will be linear with the sprocket change. 20% taller gears, means 20% better fuel economy, if you shift and ride it in the correct RPM ranges.
 

 
The lower the speed in final gear, the higher the MPG gain difference. At top speed, the bike would pretty much be consuming the same thing. (like 20MPG or so).
Also, in the city, it makes absolutely no difference, since my 5th gear is like 6th gear on a 17t front sprocket; and I can't shift into 6th at city speeds.
 

[r1limited]

 
 

 

[faffi]

Fuel consumption is affected by more than rpm. Regardless of the rpm an engine is turning, the bike needs exactly the same amount of power to do a certain speed. Less rpm means more throttle must be applied. So the only gain is in efficiency that comes from less friction and less pumping losses. Dropping revs by 20% will usually not bring anywhere near a 20% drop in consumption.

[r1limited]

Fuel consumption is affected by more than rpm. Regardless of the rpm an engine is turning, the bike needs exactly the same amount of power to do a certain speed. Less rpm means more throttle must be applied. So the only gain is in efficiency that comes from less friction and less pumping losses. Dropping revs by 20% will usually not bring anywhere near a 20% drop in consumption.

I thought throwing up was only to make room for more booze, aka consumption.  I have no dyno charts to prove that though... 
On a serious note, if you invert the power band to a more positive inertia, the drive ratio expands to a more continous motion through aggressive static build up.  BUt the FZ  s powerbadn is limited in this as there is only 1 valid point of adjustment.  I am working on a GIXXER power band swap using a Yosh GP Powerband from a 600.
 

[level41]

Fuel consumption is affected by more than rpm. Regardless of the rpm an engine is turning, the bike needs exactly the same amount of power to do a certain speed. Less rpm means more throttle must be applied. So the only gain is in efficiency that comes from less friction and less pumping losses. Dropping revs by 20% will usually not bring anywhere near a 20% drop in consumption.

There are more than just friction losses to account for. The reply would be too lengthy to get into. But there is a reduction in vacuum losses too, the engine runs at a greater efficiency not being restricted by a butterfly valve restricting it's airflow; amongst a few other reasons why MPG goes linear with gearing changes.
 
And no Dyno is needed, when you can do a simple MPG readout on the dash, and verify at the pump.

[faffi]

Vacuum losses - What I meant by pumping losses. The engine fighting to breathe through a narrow opening. Alle engines are most efficient under full throttle at max torque, that is, there is where they make the most power per burned unit. So an engine making 15 hp at max torque running wide open will use significantly less fuel than using 15 hp from a 150 hp engine.
 
But when it comes to savings from lowering rpm, there are many more things to consider. For instance, a motorcycle engine is often designed to rev high. This means valve overlap of some magnitude. This again means that under a certain RPM, spent gasses will be spat back through the cylinder and inlet valve, diluting the next cycle. Not efficient. Another issue in real life, but not in theory, is that when you lack power you may be using 10-15% more throttle than needed because the vehicle doesn't accelerate, so most will not notice. Again you are wasting fuel. At other times, you can save more fuel than the gearing difference because you can coast more and you may bring the engine into a better rev range where the inlet/exhaust work in harmony to improve efficiency.
 
I have an instant consumption readout in my car, and doing 35 mph on level ground there is virtually no change in consumption between 4th, 5th and 6th gear. However, it is very easy to use too much throttle in the taller gears since there is very little power at hand. It takes virtually no pressure on the throttle pedal to double the consumption. Also, if the load gets greater (a little hill or a strong headwind), consumption - even using the cruise control - often is greater in the taller gears. My personal experience is that the best for consumption is to use the tallest gear possible that will still allow the engine to operate without any strain. Once you start to apply more than a little throttle to maintain speed it is often more efficient to change down. YMMV.
 
 
 

[r1limited]

The reticulated over draft of circumference will cause the stagnate vapor in vacuum to become unresponsive to positive aberrations of negative reverb. This in itself causes influx in the counter swing of constant velocity of evaporative adaption including predestined protracted delimitated vaporization. Essentially what I am saying is
 

 
picture sharing img
 

[ducttapewd40]

The reticulated over draft of circumference will cause the stagnate vapor in vacuum to become unresponsive to positive aberrations of negative reverb. This in itself causes influx in the counter swing of constant velocity of evaporative adaption including predestined protracted delimitated vaporization. Essentially what I am saying is 

 
picture sharing img

but we're all getting such useful information....

[level41]

Vacuum losses - What I meant by pumping losses. The engine fighting to breathe through a narrow opening. Alle engines are most efficient under full throttle at max torque, that is, there is where they make the most power per burned unit. So an engine making 15 hp at max torque running wide open will use significantly less fuel than using 15 hp from a 150 hp engine. 
But when it comes to savings from lowering rpm, there are many more things to consider. For instance, a motorcycle engine is often designed to rev high. This means valve overlap of some magnitude. This again means that under a certain RPM, spent gasses will be spat back through the cylinder and inlet valve, diluting the next cycle. Not efficient. Another issue in real life, but not in theory, is that when you lack power you may be using 10-15% more throttle than needed because the vehicle doesn't accelerate, so most will not notice. Again you are wasting fuel. At other times, you can save more fuel than the gearing difference because you can coast more and you may bring the engine into a better rev range where the inlet/exhaust work in harmony to improve efficiency.
 
I have an instant consumption readout in my car, and doing 35 mph on level ground there is virtually no change in consumption between 4th, 5th and 6th gear. However, it is very easy to use too much throttle in the taller gears since there is very little power at hand. It takes virtually no pressure on the throttle pedal to double the consumption. Also, if the load gets greater (a little hill or a strong headwind), consumption - even using the cruise control - often is greater in the taller gears. My personal experience is that the best for consumption is to use the tallest gear possible that will still allow the engine to operate without any strain. Once you start to apply more than a little throttle to maintain speed it is often more efficient to change down. YMMV.
 
 

Yes, you're right about that. Which is why some cars have a CVT. To keep the engine in the right RPM range.
I have a turbo engine in my car, and can see what you're talking about in an exaggerated way.
If I would keep my speed at 40mph, my instant mpg is:
75 MPG in 6th
68 in 5th
60 in 4th.
Big difference!
 
However, if I accelerate hard, since I have ride by wire, mpg numbers are almost identical in 4th, 5th, or 6th, however 4th gets me up to speed faster than 6th, causing an overall mpg loss if I stay in 6th.
 
For that reason, there is an optimal RPM range for each acceleration.
Taller gears allow you to downshift to first, if you must, for faster acceleration. Shorter gears do not allow you to ride easier on the highway, because 6th is final gear... However, the greatest benefit from taller gears comes from keeping the throttle steady, which is what you'd do on the highway or interstates.
 
Mild acceleration at 80mph in 6th with the 17/38t is very similar to flooring an econo car at those speeds in a lower gear (aka 5th).
The FZ can still downshift to 4th gear where it's right in the powerband, similar to a stock 5th gear, and zip through traffic pretty well.
 
Wide open throttle acceleration, is best done at 8.5k RPM for fastest acceleration, and at 6.5k RPM for best mpg.
But, the slower the acceleration, the lower the RPM can be to increase mpg.
At a constant speed (no acceleration), best mpg the bike can offer, is at about 3k rpm, without lugging. With stock gears, that is about 45mph. With modified sprockets, that would be almost 55mph.
 
I believe it makes most sense to equip your bike with the sprocket setup for the speed you'd be cruising the most at. If you're not cruising, but accelerating a lot, it would make sense to optimize the bike for that, and get a smaller front cog, and a larger rear.
But not for me.I find a 17/38t nearly perfect for the highway, and should be able to do about 5mph faster top speed, than a stock bike.
 
As far as recuperating exhaust gasses, at 3k RPM it appears that the exhaust provides a nearly constant back pressure, which only mildly increases with higher rpms and load.

[r1limited]

The reticulated over draft of circumference will cause the stagnate vapor in vacuum to become unresponsive to positive aberrations of negative reverb. This in itself causes influx in the counter swing of constant velocity of evaporative adaption including predestined protracted delimitated vaporization. Essentially what I am saying is 

 
picture sharing img

but we're all getting such useful information....

Just had to be repeated.    I never new what an RPM was until now, and I thought it was a rock band  
[video src=https://youtu.be/y2R3FvS4xr4]
 

[pattonme]

@r1limited writes academic papers for living I see. Where stringing random words together is peer reviewed and published in "accredited" journals.
 
> I am working on a GIXXER power band swap using a Yosh GP Powerband from a 600.
 
So 4 strands of 1/2" wide rubber band? How many twists do you need to put into it and what size dowel do you use on the end? Do you double or triple twist? (think rubberband air planes from your elementary school days)

[r1limited]

@r1limited writes academic papers for living I see. Where stringing random words together is peer reviewed and published in "accredited" journals. 
> I am working on a GIXXER power band swap using a Yosh GP Powerband from a 600.
 
So 4 strands of 1/2" wide rubber band? How many twists do you need to put into it and what size dowel do you use on the end? Do you double or triple twist? (think rubberband air planes from your elementary school days)

My academia prowess is an acclaimed attribute from the abject distinction in the in-depth study of forumology.
 
Now back to powerbands
 
Twists are only relevant if the galvanized nature of redistribution of recycled rebound.  This is caused by the reverberation of gyroscopic impedance propelled by damping recoil.  In short if you use the Blue Yosh GP over the Green the twisting dynamics is far more resistant to condensed oscillation.  There is a fine balance between condensed oscillation and repeat overture encapsulation. 
 

[Guest 2wheeler]

@r1limited writes academic papers for living I see. Where stringing random words together is peer reviewed and published in "accredited" journals. 
> I am working on a GIXXER power band swap using a Yosh GP Powerband from a 600.
 
So 4 strands of 1/2" wide rubber band? How many twists do you need to put into it and what size dowel do you use on the end? Do you double or triple twist? (think rubberband air planes from your elementary school days)

My academia prowess is an acclaimed attribute from the abject distinction in the in-depth study of forumology. 
Now back to powerbands
 
Twists are only relevant if the galvanized nature of redistribution of recycled rebound.  This is caused by the reverberation of gyroscopic impedance propelled by damping recoil.  In short if you use the Blue Yosh GP over the Green the twisting dynamics is far more resistant to condensed oscillation.  There is a fine balance between condensed oscillation and repeat overture encapsulation. 

Guys, you are going to have to be careful on your posts.... these last two are surely going to short circuit Level41, or is it cause him to implode
 
 
 
 

[pattonme]

Poor @2wheeler , you thought the forum was an escape from the mind-numbing blather of techno/legal mumbo-jumbo pretending to be written English that you get to read at your day job? Sorry to ruin it for you, man...
 

[level41]

If you're just here to make fun, please take it elsewhere!
 
r1limited, there's plenty of forum space to troll.
I would appreciate if you can move your offtopic comments elsewhere, thank you.

[Cruizin]

A couple of you guys in this thread clearly do not like the other. I suggest that you try to get along or ignore ea other. I will not pick sides if I have to get involved.

[r1limited]

A couple of you guys in this thread clearly do not like the other. I suggest that you try to get along or ignore ea other. I will not pick sides if I have to get involved.

Dislike? Nay, how can one dislike someone based on typed words, A study on communication in the age of technology if I recall from MIT or wherever sites that 85% of communication is visual and audial.  This leaves 15% to be understood based on written.  The study sited, tone, body language, proximity aka face to face determines the mood as well as the ability to listen and comprehend what is being stated.    
I was simply having fun, I dislike no one, well maybe my future son in law yea I dislike him he is a putz  or maybe Honda riders, definetly suzuki and kawi most definetly HD, and did I ... "But I Digress"
 
I will be content reading the conitued saga of what...... Humm what shall this thread be named? (Taping chin while contemplating in space)
 

[pattonme]

A study on communication in the age of technology if I recall from MIT or wherever sites that 85% of communication is visual and audial

Sorry, I can't let this one go. From M(idgets) I(n) T(own)? Oh heavens no! The study (were there multiple?) was by Carnegie Mellon Univ, thank you very much. I read my prof's paper before it was published - thanks to borrowing time on her Quadra 840 after hours to write a MacOS 7 app.

[r1limited]

A study on communication in the age of technology if I recall from MIT or wherever sites that 85% of communication is visual and audial

Sorry, I can't let this one go. From M(idgets) I(n) T(own)? Oh heavens no! The study (were there multiple?) was by Carnegie Mellon Univ, thank you very much. I read my prof's paper before it was published - thanks to borrowing time on her Quadra 840 after hours to write a MacOS 7 app.

Happy to assist, I did not recal where the study was as established in this out take " if I recall from MIT or wherever sites" thus not 100% confident in who what where.  But when I was workign wit Einstrin on Collaborative Nuclear Fusion and assisted n his theory of relativity, ol Ein (ya we called him Old Ein)  he used to say, Oopsala when he made a mistake, so Oopsala