Riddle Me This: Same MPG, Lower Range

[EASt]

So, ever since I put in the HyperPro shock and forks, I've noticed some things:

1. Filling my tank to the top only gets me about 250 miles-to-empty. Before the HyperPros, I would go 300 easy on a tank.
2. My calculated MPG is the same now as it was before the HyperPros.
3. It's way, way easier to get the ST1300 on center-stand with the HyperPros.

Am I correct in concluding that the stance of my ST has changed? Also, why would that affect fuel capacity? Or, is the fuel indicator blinking earlier due to a new angle, but I actually have more fuel than would normally trigger the blinky last light?

This doesn't add up for me.

Oh, and, no known fuel leaks.

 

[Igofar]

So, ever since I put in the HyperPro shock and forks, I've noticed some things:

1. Filling my tank to the top only gets me about 250 miles-to-empty. Before the HyperPros, I would go 300 easy on a tank.
2. My calculated MPG is the same now as it was before the HyperPros.
3. It's way, way easier to get the ST1300 on center-stand with the HyperPros.

Am I correct in concluding that the stance of my ST has changed? Also, why would that affect fuel capacity? Or, is the fuel indicator blinking earlier due to a new angle, but I actually have more fuel than would normally trigger the blinky last light?

This doesn't add up for me.

Oh, and, no known fuel leaks.

My guess would be since it handles better, its probably got something to do with your throttle hand LOL.
It would be easier to get on the centerstand due to the taller stance.

 

[sennister]

Springs were not your only change Erik. Remember you changed the fuel sending unit in the upper tank? Maybe there is a difference there. When you fill up at 250 miles how many gallons are you adding? Are you missing a hammer or any other large tools?

Edit: Or another possibility. You have a Russle now and those 300 miles actual only feel like 250.

 

[TripleJ]

Are you missing a hammer or any other large tools?

Now that right there is funny!

 

[EASt]

I am pleased to see that Dave, for once, has decided not to answer my issue with a deeply thought out technical response, and has instead taken the route that I always do: Be a smarty-pants!. Oddly enough, when I lifted my tank to replace my MAP sensor last week, I found an old hose clamp under there. So, the hammer theory isn't all that far off.

However, the fuel MPG has been based solely on fill-ups and odometer readings. The broken sensor shouldn't affect my overall range. It just doesn't make sense to me.

Now, Igofar would ordinarily be correct in that the HyperPros have encouraged me to keep a bit more throttle open in turns, but (using Fuelly.com since 2007) my MPG has remained an average 44 (with one major dip when my T-Stat failed). I drive my ST like a granny and always will.

 

[sennister]

Well if the MPG is the same and the range less, me thinks you are putting in less gas than you used to. Does Fuelly.com show you gallons used or just average. It is still possible that the new sending unit is thinking it is empty and triggering the 2 bar count down premature. Remember MPG is calculated by range/gallons = MPG.

From my understanding the upper sending unit get to the "empty" reading and then starts the countdown. That last two bars is calculated based off normal fuel use based on MPG. That is why the last two bars and miles to empty have to be taken with a grain of salt.

Because of this you may find that you get better range on two bars than you used to. It is hard to say because you did your springs over a year ago but last year you were dealing with a faulty fuel gauge.

So this might explain it. Or the hammer does....

 

[flyfisher]

So do you fill on the sidestand or center stand? Maybe the lean angle is more so the cap is lower than it used to be....more empty tank on the upside.....just thinkin'..............

 

[Gene]

Take out some preload !!

 

[T_C]

So do you fill on the sidestand or center stand?

You put a stand down to fill?

 

[sennister]

You put a stand down to fill?

I know I don't. I don't put the center stand down either. I just sit on it. It is faster that way.

The side stand is a good point though. From talking to RichR who also did the same spring mod at the same time, the bike sits taller. So in theory it would lean further and maybe fit less gas. 50 miles less gas? Not sure but it would in theory be less.

I still stand by the point that if the MPG is the same and the range is less, then it isn't an aero thing. He has to be burning less gas. It is the only way to make the math work out. So why is he burning less gas? The fuel sensor is new, is it reading things different? There is a possibility that the bike is leaning more when getting refueled. Then there is the hammer theory.

 

[EASt]

I used to fill whilst straddling back when I had my VFR - it was easier and lighter to do so. Also, I saw a video years back of a fellow straddling a motorcycle, pumping gas, spontaneously burst into flame. Scared the bejeebus outta me.

Preload? What's that? Talk a bout a knob I've never played with much! :roll:

Dave may be on to something: Before the new Suspension Stance, I would put in ~5.89 gallons at 250 miles in 2009.

Now, after the new suspension, I put in 5.44 with the same miles. I always have, and still do, fill up to the tank tab on center stand.

So, new suspension has tilted the motorcycle's level line? Bringing the fuel up to the tab sooner than with the stock suspension?

 

[sennister]

I used to fill whilst straddling back when I had my VFR - it was easier and lighter to do so. Also, I saw a video years back of a fellow straddling a motorcycle, pumping gas, spontaneously burst into flame. Scared the bejeebus outta me.

Preload? What's that? Talk a bout a knob I've never played with much! :roll:

Dave may be on to something: Before the new Suspension Stance, I would put in ~5.89 gallons at 250 miles in 2009.

Now, after the new suspension, I put in 5.44 with the same miles. I always have, and still do, fill up to the tank tab on center stand.

So, new suspension has tilted the motorcycle's level line? Bringing the fuel up to the tab sooner than with the stock suspension?

Nope, take an inventory of your tools....




EDIT: The front would be higher based on what Rich has said. So it is possible.

 

[EASt]

Funny thing is, I am missing a hammer.

 

[SteveST1300]

With the added ride height from the Hyperpro's my bike leaned over quite a bit more on the side stand until I took out some pre load then it sat a bit better.

 

[EASt]

With the added ride height from the Hyperpro's my bike leaned over quite a bit more on the side stand until I took out some pre load then it sat a bit better.

This is the same case with mine.


Sent from my iPhone using Tapatalk

 

[sennister]

Funny thing is, I am missing a hammer.

I am shocked that you haven't accused me of managing to bug your garage somehow.

 

[Gene]

Preload Who said that ? But lowering the reat alot losses the crisp handling those new springs give when the bike sits in cruiser mode , high front low rear makes for a slow handling pig in my opinon , more fun to loose a few onces at fill up !

 

[Gene]

Or put a pad on the bottom of the stand foot to help get the angle back to mear stock .

 

[sennister]

Preload Who said that ? But lowering the reat alot losses the crisp handling those new springs give when the bike sits in cruiser mode , high front low rear makes for a slow handling pig in my opinon , more fun to loose a few onces at fill up !

He also said he fills his bike with it on the center stand so I don't see how preload can be a factor. Unless it leaks out of the overflow vent when he takes the bike down. Though fuel loss doesn't appear to be the issue. It seems to be that he can't get as much gas in as he did in the past. He seems to be down about .45 gal in capacity. So what is the displacement of a hammer? Either way the only way I see the springs as a factor is if he installed the old ones in the fuel tank, or the higher front end changing the angle of the filler neck. Personally I find it hard to believe it could possibly make 1/2 gallon difference as that is quite a bit.

So if it isn't a hammer I am going to stick with my first answer which was the upper sending unit reading things a bit different. His bike is signalling that it is low before the upper tank is empty. Well as I type this I thought that maybe there is a difference in the angle of the bike because of the springs and that is causing the sending unit to read empty before it is. Still 1/2 gallon is quite a bit. I would be leaning toward the float arm being tweaked a little being the issue over the angle of the bike.

One way to find out. Carry a little spare gas and run it dry to see how far you can really go on E.

 

[EASt]

Ultimately, Dave's right. If I'm gonna get to the bottom of this, I need to bring a mason jar of gas, and ride till the engine kills. Also, it could be in my head. It could be that I'm driving half-a-gallon more maniac than I used to (although my MPG is still good).

Anyone got a glass jar I could borrow?

Oh, and, I need to borrow a hammer, too.