Gas mileage

[blackmetoc]

So, I used to get, maybe 200 miles, giver or take a few from fill up to gas light trigger. Now I am getting 175 to 180 miles. I have changed out the air filter a couple times through this, a couple sets of tires from regular, to darkside and back to regular. I have around 55k on it. Is it a computer setting? Has anybody else seen this drop in mpg? It is not horrible, but it is a question to ponder.

[wjduke]

Has it idled a lot? I see you're down south. Up here, mileage drops a bit during colder weather.....just one thought.

[unsub]

What condition is your battery in, and is it the original? Maybe time to look at replacing the battery.

[53driver]

I'm thinking you are crossing the nefarious "3150 RPM" threshold whilst riding!
If you keep RPMs below 3150 (~72mph), you go 200+ miles until the Low Fuel Light comes on. Above that RPM, gas mileage goes down quickly.

Another thing to ponder is your Low Fuel light sensor. I know when mine used to come on, if I stopped to refill it within a mile or two, it would take 5.6 to 5.7 gallons. Now when it comes on (95k on the odo) I am only getting 5.4 gallons in.

I would do that computer reset (including disconnecting the battery) to rule that portion out.
Then just check your logbook/documentation to see if there are any other trends.

Cheers,
Steve

[zeus661]

What condition is your battery in, and is it the original? Maybe time to look at replacing the battery.

Battery can affect gas mileage? How?

[pdxstriper]

I get 42 MPG. Hot, cold, fast, slow. No matter what I do I get 42 MPG. That’s all.

[VaBob]

About 42 here also.

[Sorcerer]

Did you change your windshield? Add wind deflectors.

[3Chief]

I'm thinking you are crossing the nefarious "3150 RPM" threshold whilst riding!
If you keep RPMs below 3150 (~72mph), you go 200+ miles until the Low Fuel Light comes on. Above that RPM, gas mileage goes down quickly.

Another thing to ponder is your Low Fuel light sensor. I know when mine used to come on, if I stopped to refill it within a mile or two, it would take 5.6 to 5.7 gallons. Now when it comes on (95k on the odo) I am only getting 5.4 gallons in.

I would do that computer reset (including disconnecting the battery) to rule that portion out.
Then just check your logbook/documentation to see if there are any other trends.

Cheers,
Steve

Ditto, I wasn't sure of the exact rpm but over 4k and my mileage drops to low thirties. At the rally riding two up I was getting 50+ but we were riding much more sedate than I do solo.

[53driver]

Ditto, I wasn't sure of the exact rpm but over 4k and my mileage drops to low thirties. At the rally riding two up I was getting 50+ but we were riding much more sedate than I do solo.

I have been searching for the "bucket RPM" of this motor...
I.e. "I'm low on fuel and I need max range RPM for 5th gear"
It's somewhere between 2300 and 2800.

If I should cruise at 85+ (ha!) my mileage goes down to low/mid thirties also.
I don't have any data for sustained ops at 4000 RPM although that would make for an interesting data gathering expedition....hmmmm.

[3Chief]

I have been searching for the "bucket RPM" of this motor...
I.e. "I'm low on fuel and I need max range RPM for 5th gear"
It's somewhere between 2300 and 2800.

If I should cruise at 85+ (ha!) my mileage goes down to low/mid thirties also.
I don't have any data for sustained ops at 4000 RPM although that would make for an interesting data gathering expedition....hmmmm.

On my return trip from San Diego I did an Iron Butt and pretty well stayed 85-90 from Bakersfield to Tacoma aside from the nasty bit in the Siskiyou's. I stayed in the low 30's for mpg. It was also cold/wet and generally unpleasant for the last half. It was below 50 degrees almost the entire trip and I seemed to remember hitting 28 degrees when I summited the pass.

[unsub]

Battery can affect gas mileage? How?

That's a good question. When I read blackmetoc's post I did some reading. It seems that an unhealthy battery can result in poor spark plug performance and a heavier load on the alternator / motor, and poor injector performance to name 3 issues that might result in change to fuel economy. Hell, maybe crappy gas or easing up on the throttle is the answer. But...modern bikes depend almost entirely if not completely on electronics to run efficiently, so these things makes sense to me.


*blackmetoc Let us know what you find your issue to be.

[Fourks]

When running the bike runs off the alternator. The battery would not effect gas mileage.

[jm21ddd15]

Not sure about what fuel you use, or is available in your area, but up north we have a "winter blend" of fuel, that the government make the fuel companies run, supposedly, for smog or pollution crap. And it does cost us more than the summer blend. Except for the seasonal "holiday price scams".

[JWExperience]

When running the bike runs off the alternator. The battery would not effect gas mileage.

I don’t entirely agree. The battery is still in the electrical loop and running with a bad battery can cause other parts like alternators to fail.

[Fourks]

I don’t entirely agree. The battery is still in the electrical loop and running with a bad battery can cause other parts like alternators to fail.

Very true, but the statement is that it affects gas mileage, I suppose that an alternator that is full fielding might increase the load slightly, but not something I would think you could see in your gas mileage.

[98valk]

How about spark plugs. How old are yours?

[JWExperience]

Very true, but the statement is that it affects gas mileage, I suppose that an alternator that is full fielding might increase the load slightly, but not something I would think you could see in your gas mileage.

I think it’s plausible that a weak link in that spark side of the system could cause the plugs to not fire at their full potential and not burn the fuel efficiently.

[Fourks]

I think it’s plausible that a weak link in that spark side of the system could cause the plugs to not fire at their full potential and not burn the fuel efficiently.

wouldn’t one also have codes for catalytic efficiency or random misfire?

[blackmetoc]

Thanks for the feedback, I'll try that. I could put a new battery in. I think the original is the one in there.

[blackmetoc]

They are also due, but I don't think they were when I saw the drop. I saw an appreciable drop in San Diego, but I was riding hills as opposed to here on the Gulf Coast. As for crossing the magic RPM-ness, (>~72mph), un, that would be speeding. I would NEVER do that!!

[blackmetoc]

They are also due, but I don't think they were when I saw the drop. I saw an appreciable drop in San Diego, but I was riding hills as opposed to here on the Gulf Coast. As for crossing the magic RPM-ness, (>~72mph), un, that would be speeding. I would NEVER do that!!

Quick check in, no lightning hit me.

[tenxxx]

Don't forget about the cheap gas thats going around. While on the road from Ohio to FL, I watched the milage a bit.
One tank of gas was crap. It came from Marathon.
I try to get my gas at BP or Sunoco but when your on the road it aint that easy.

[blackmetoc]

Did you change your windshield? Add wind deflectors.

No and no. I may be fatter

[blackmetoc]

Don't forget about the cheap gas thats going around. While on the road from Ohio to FL, I watched the milage a bit.
One tank of gas was crap. It came from Marathon.
I try to get my gas at BP or Sunoco but when your on the road it aint that easy.

I used the non-ethanol down the street. I have since I have had this bike.

[Fourks]

So, I used to get, maybe 200 miles, giver or take a few from fill up to gas light trigger. Now I am getting 175 to 180 miles. I have changed out the air filter a couple times through this, a couple sets of tires from regular, to darkside and back to regular. I have around 55k on it. Is it a computer setting? Has anybody else seen this drop in mpg? It is not horrible, but it is a question to ponder.

Wonder if it could be a slow responding O2 sensor? Did you see the drop when you went dark, and has it improved going back to the correct tire? Also, have you added any assessories or increased the windshield height?

[blackmetoc]

Wonder if it could be a slow responding O2 sensor? Did you see the drop when you went dark, and has it improved going back to the correct tire? Also, have you added any assessories or increased the windshield height?


I saw it when I went dark, it never improved when I went back to a MT

[Fourks]

Might be worth trying a new O2 sensor. I don't see that Honda monitors for slow O2 response.

[unsub]

Look all, take this for what it is but I happen to come across this youtube video. The presenter is somewhat eccentric but he explains in a little detail why a poor battery could cause a drop in MPG. This was completely coincidental but seems to confirm the the information I had gathered from other sources.

Again remember, eccentric - youtube - internet, so don't shoot (me) the messenger. This is all for purposes of civil discourse and of course to help the OP.:cheers:

https://youtu.be/rEDkdPJHScA?t=165

[Fourks]

Look all, take this for what it is but I happen to come across this youtube video. The presenter is somewhat eccentric but he explains in a little detail why a poor battery could cause a drop in MPG. This was completely coincidental but seems to confirm the the information I had gathered from other sources.

Again remember, eccentric - youtube - internet, so don't shoot (me) the messenger. This is all for purposes of civil discourse and of course to help the OP.:cheers:

https://youtu.be/rEDkdPJHScA?t=165

a little eccentric is being to kind. He does have a shirt with his name on it, so must know what he’s talking about:-) not even using the correct battery tester which is a carbon pile tester. The battery starts the car, the alternator powers the cars electronics. The battery is out of the loop.

[tenxxx]

If it were the battery, it would have to be so bad that it wouldn't start the bike.
While running, the alternator charges the battery and runs the electronics.
The battery isn't out of the loop, but its just sitting there absorbing any sudden spike in the system. Be it a drop in voltage or a rise.
My alternator puts out 14.4 v at idle with head lights, tail lights and what ever else.Thats a load of 3 amps or more.

[Fourks]

The battery is still in the circuit but it's base voltage and no longer has input once the potential of the alternator is online. So it is " out of the loop".