will someone check my math homework.... MPG

[StickyTeflon]

So i wanted to know how far i could go on a single tank of fuel, but I've never had an opportunity to burn up 2.9 gal in a single shot.
So this is what i did and I'd like some help checking for errors

1gal = 128oz

I mixed up 3 gal of gas (384oz)

i completely drained my tank / reserve also.

I pored in some fuel and rode until i had to leave.

I rode 27 miles per my odometer.

I drained the tank and measured it in a graduated container 16oz at a time.

I was left with roughly 241oz total left over(including gas can) of the original 384oz.

so 143oz to go 27 miles. to find the total mileage of my tank :

2.9gal x 128 = 371.2

143oz 27ml
------ = ------
371oz ( X )ml


371x27 = 10017

10017/143 = 70 miles total tank + reserve

measured reserve was aprox. 88oz

so main tank = EDIT: 53 miles

and reserve = 17 miles

this is assuming that the 2.9 gal includes the reserve also (can someone confirm?)

does this look right to you guys that like to do math, or is my logic flawed here??

Remember doing cross multiplication in school and thinking "when am i ever going to use this"

Is this typical mileage
I'm running 12t front and 51t rear on 97 kdx220

Thanks
Sean

[IdahoCharley]

Numbers are good on the total tank but your main tank and reserve numbers are off. 63 +17 = 80 which is more than your main tank and reserve calculated amount. 53 on main and 17 on reserve based upon your numbers.

Of course reality needs to enter in - 1) reserve is never completely drained in the real course of running out of fuel 2) no two rides will be exactly the same in mpg 3) Assumed that when you said three gallons you were spot on verses 3 gallons and gas and the 12 oz of premix oil added on top of the gas: but you did say "math" review and not procedure review did you not?

I think 60-75 miles per tank is likely about what our 200 averages in trail riding.

[StickyTeflon]

your right about the 17 and 63. duh.. the only thing worse than math is late night math

I was planning on a little allowance for your other points and didn't plan on riding 35 miles out and back.. but its nice to know your estimated window.

Hatfield and McCoy here i come....

Thanks
Sean

[quailchaser]

I can't argue your math, as I skipped all that and just looked at your final numbers. No offense, your math is probably perfect...my attention span is just not that...

2.9 gallons is the total fuel capacity.

Your logic may or may not be flawed. If you ride the same terrain; under the same quality of jetting; with the same quality of fuel; with the same premix mixture ratio; with the same brand of premix as your test ride, your milage should be virtually identical.

I've had rides with the KDX where I ran out of fuel at 40 miles. I've had rides where I just flipped to reserve at 75 miles. I was on a fairly technical ST ride that turned from a 30 mile ride to a 45 mile from he!!. I was on the KX with the stock 2.2 gallon tank and did not run out of fuel. I must admit that I believe that the only fuel left in it at the end of that ride was in the float bowl.

If you do a search, this topic has been covered before. I believe the responses where pretty much you milage may vary. The more you ride, the more you'll be able to judge what kind of milage you'll get out of the KDX for different types of rides. 70 miles is definitely within the capabilities of the KDX.

[Jeb]

Hatfield and McCoy here i come....

Thanks
Sean

When are planning on riding Hatfield and McCoy?

[AZRickD]

When riding mostly ST, I switch to reserve at around 50 miles.

Anybody know the numbers on the reserve stopcock setting? How many ounces does that allow?

Rick

[2001kdx]

Reserve is 0.8 gallons.

[StickyTeflon]

When riding mostly ST, I switch to reserve at around 50 miles.

Anybody know the numbers on the reserve stopcock setting? How many ounces does that allow?

Rick

In the garage i drained the tank down to the reserve and measured from reserve to empty and got roughly 88 - 89oz

88/128 = .7 gal

But i think theres a small amount in there you'll never be able to burn.

Sean.

[StickyTeflon]

Hatfield and McCoy here i come....

Thanks
Sean

When are planning on riding Hatfield and McCoy?

I'll be there the 13th and 14th and maybe part of the day the 15th (June) depending on how sore i am

I've never been there before and i'll be staying in Gilbert, near the Browning Fork area. I really need to check out Little Coal River though also, because it's got alot of green trails for the wife and kid.

This trip is a recon / mini vacation. My daughter is at grandmas for the summer and the wife has to work... so i get to play by myself. My wife and daughter both ride and I'm scouting H&M for future family vacation riding areas.

[AZRickD]

I did my worst MPG ever yesterday.

Janik, "the unbearable bleakness of being," invited a half-dozen of us to come play in the hills of Flagstaff. I was going to re-jet, for the riding at 7,000 to 9,000 feet (and 80F), but I decided not to.

With my tank full, and running lots of single track, I had to hit reserve at around 30 miles. This cut short the last five miles of ST, as I wanted to get the extra MPGs that sixth gear allows on the jeep trails to get back to the stage.

Rick

[Wudscrasher]

143 oz / 128 oz = 1.12 GAL

27 miles...........X
---------- = ----------- = 24.1 MPG
1.12 GAL ......1 GAL

2.9 GAL x 24.1 = ~70 Miles/Tank

There ya go. The other guys are right about the varying conditions, terrain, elevations, etc. I got roughly 40 MPG on a jaunt in Utah, but that was mostly dirt roads with some sand wash and ATV trail thrown in.

Make sure your jetting is spot-on, and if you ride conservatively, you may get a few more MPG out of it.

--C.J.

[canyncarvr]

"I can't argue with your math...'

Me neither. 'Cuz I didn't bother going through it.

ANY 'What kind of mileage should I get?' sort of question will not get any response of any value.

'Will I get less than 20 miles out of a tank?'

Yep.

'Will I get more than 80 miles out of a tank?'

Yep.

See? It's all VERY exact!

[quailchaser]

I did my worst MPG ever yesterday...
I had to hit reserve at around 30 miles.

Rick

If you stop spending so much time on the ground, you tend to get better milage (even with a poorly jetted bike) Them pine needles are not very forgiving when it comes to traction.

[2001kdx]

"I can't argue with your math...'

Me neither. 'Cuz I didn't bother going through it.

ANY 'What kind of mileage should I get?' sort of question will not get any response of any value.

'Will I get less than 20 miles out of a tank?'

Yep.

'Will I get more than 80 miles out of a tank?'

Yep.

See? It's all VERY exact!

Yup. It varies SO much. I've gotten 20 miles on a tank when playing around in open areas, hit the woods, 1-3 gear stuff and 80 can be easily gotten.

[AZRickD]

If you stop spending so much time on the ground, you tend to get better milage (even with a poorly jetted bike) Them pine needles are not very forgiving when it comes to traction.

This was my first introduction to "woods riding" (Arizona Ponderosa Pine and aspen, anyway).

I did my first slo-mo into a tree. Got my forearm whacked by a sappling. And then when I finally got a chance to get into a groove, and rail a berm to catch up to everybody, the berm turns out to be a pile of pine needles.

Ssssssssssssssssssssssslide.

Rick

[Colorado Mike]

lol

I once was catching up to a fast guy in our party and was railing the berms (real ones). Suddenly, one of them just broke away, and off I went just about horizontal through some sapplings. I went a long way too. Ever feel like you're falling in your sleep? A buddy of mine saw it from the last switchback and couldn't stop laughing.

[2001kdx]

"Ever feel like you're falling in your sleep?" mmm... Only ALL THE TIME! I'm imagining my self riding and then pow! A tree hits me. Then I wake up all startled. I did it in english class one time, and I had to explain to everyone what happened lol

[AZRickD]

I re-did my fuel.

I used 1.75 gallons in 35 miles (including at least five miles of sixth-gear forest road). So, with the forest road included, I got about 20mpg. With the forest road omitted, I did 17.5mpg. Both of which I consider normal for some 1st and 2nd gear single track with some hill climbs.

Rick

[2001kdx]

How's this for MPG - What sucks more fuel, higher RPM's, or Higher speed/gear?

[quailchaser]

How's this for MPG - What sucks more fuel, higher RPM's, or Higher speed/gear?

Yes.

I used 1.75 gallons in 35 miles

That's much better than the full tank scenario. So, what happened to the other 1.15 gallons? You didn't replace your KDX gas cap with one of those cool high tech 1/4 turn KTM caps? BTW, That's right around what I typically get on the KX for the mostly ST rides.