Bad Gas Mileage....while on a road trip...yikes!

[mark@umt.com]

Hey all,

I have a 2000 I/S and usually get around 300kms or 186 miles per tank....however...I'm currently on a road trip and for the last three fill ups, I'm only getting 200kms or 124 miles per tank...that's a 1/3rd less mileage per tank!  Yikes!!!

I'm currently going west along IS 40 around 125km or 70 mph, it's hot 40C or 100F ++.  Have recently changed the oil...not burning any...not burning coolant...tire pressure is typical.  I know I got a bad tank of gas because after I got that fill up, that's when I started noticing the issue...however, three or four tank ups later, I thought that should have cleared up the problem by now.

Any suggestions?!?

Thanks,
Mark

[Former BMW Guy]

Choke sticking on?

JP

[mark@umt.com]

nope...choke fully disengaged.

[Hoser]

Strong headwind?  70 mph against a 40mph headwind is like going 110 mph.  Hoser

[mark@umt.com]

I don't think so....I went through wind turbine valley west of oklahoma city....and they weren't even turning.  Plus I have gone that fast before....but never for this long and steady (500+ miles per day).  So I don't think that's it either.

But thanks to both of you for the suggestions.

Any additional thoughts, ideas or suggestions?!?

Thanks.
Mark

[MarcusS]

Make sure the cover on your petcock is not leaking. The diaphragm can go out anytime. There is a hole on the bottom that can leak gas out. Run your hand under it and see if it is wet.

Timing air and fuel all part of the economy but a leak is a leak.

[Bone]

My 98 Tourer ran out of gas in the New Mexico desert 3 years ago. Had been running 75 -80 mph into a wind. Hit reserve way early and never saw a gas pump. I was close a young guy picked me up I was walking and the next station was a mile away. The wind and the speed was to much the gas evaporated.  101º on my thermometer it could have been a dangerous situation.
Buy gas early in those conditions.

[Challenger]

Had the o-ring on the fuel tube between #3 & #5 carb fail once. mileage dropped fom 36 to 25. Would not leak sitting because the petcock was shut off, could not smell it or see when hot, found it by starting it up cold and watching until it started dripping out of the tube. Just a thought!

[Pappy!]

High temperatures also play an important part. You lose horsepower as the temps go up so the throttle has to be twisted a little more to compensate. You mentioned 100 degree temps and that definitely has something to do with it. Air ioses density as the temps rise.
When I am flying and its hot I always calculate how much more runway I will need based on my load and the temp, pressure-altitude. They all play a part in taking away your available horsepower.

[Former BMW Guy]

Pappy's post made me think of another thing: the air filter could be clogged causing a rich mixture..

JP

[eric in md]

its how it is when your on the hammer... sorry these bikes are gas hogs if you twist it up.. my i/s had been out of gas at 89 miles before  out of reserve shut off at 89 miles .. when we was out west turning miles with lots of smiles ..

[Sonny]

When running 70 and above I never get more than 120 to 130 miles on a tank before switching to reserve on my 99 standard. Back roads, 45 to 60 yes much better.

Might not be anything wrong at all. Could be a multitude scenarios going on at the same time, roads, wind, load, gas quality ??

[RicCA]

Maybe put some carb cleaner in next tank or two and see if that does anything.
Ric

[Six-Cylinder Hooligan]

Try running a can of Sea-Foam thru it??

[bassman]

What tire pressure are u running?  I hope at LEAST 40 psi Front and 42 psi Rear. 

[Pappy!]

Yep, at turnpike speeds (75 or so) I am usually switching to reserve around 125-135 miles.

[deadwood]

On my 2001 I/S I've got anywhere from 205 miles to reserve to 120 to reserve on road trips.
I've found the wind, mountains, heat and your right wrist are all factors but one of the biggest is fuel with ethanol.

On some round trips I've notice the drop in mileage coincided with going thru certain states.

Keep riding. It will get better.

Hey all,

I have a 2000 I/S and usually get around 300kms or 186 miles per tank....however...I'm currently on a road trip and for the last three fill ups, I'm only getting 200kms or 124 miles per tank...that's a 1/3rd less mileage per tank!  Yikes!!!

I'm currently going west along IS 40 around 125km or 70 mph, it's hot 40C or 100F ++.  Have recently changed the oil...not burning any...not burning coolant...tire pressure is typical.  I know I got a bad tank of gas because after I got that fill up, that's when I started noticing the issue...however, three or four tank ups later, I thought that should have cleared up the problem by now.

Any suggestions?!?

Thanks,
Mark

[KSDragonRider]

I just got home from Vacation on the valk.  Pulling an overloaded trailer, 2 up, in the wind every day, i got between 100 and 135 between fill ups.  The worst was 99 miles from fill up to fumes... but it was bad bad gas i got where i could get gas, and i knew when i got it that it was bad, but i had to get off the reservation to get anything any better, so hammer down 80+ off the res and got gas in Buffalo when i ran out.

I never make more than 30 unless i am alond on all 55mp roads, and that does not happen often.

[mark@umt.com]

Sorry for no updates...no wifi until today.

So....I think as someone put it...its multiple factors.  I am now in the 75-85F temps...going 65-70mph and am getting 32-36mpg's on the last few fill ups.  I think it was a combination of wind....not to strong but strong enough...temp...altitude...the right hand....and potentially the choke as the first individual responded.  I twisted the choke back and forth a few times that night to be sure both sides of the sliders were moving...the next day...cooler temps...lower altitude...less wind...and BAAAAAM....34mpg's! 

Thanks all for the responses....I think I might still have some sludge residue from that bad gas fill up....but at least hitting 32+mpgs....big smiley face on me and the pocket book! 

[Daddie O]

I drive around 85 mph, often against a headwind, and I get 31mpg.  I do love the new belly tank I installed.  224 miles before I switched to reserve, and I did 85-100 for pretty much the whole trip.



I took this pic just before adding the belly tank and doing the shiny desmog.  I've gotta take one now that I added the tank and the spark plug/valance covers.

[old2soon]

I've had days on my I/S when I drove her hard and she ripped thru the gasoline. I've had days on my I/S when I've driven her fairly easy and she ripped thru the gasoline. Of course the opposite has happened in either case but most generally when you drive hard and fast these beasts rip thru the gasoline.  When I plan a long trip I run my figures at 28 M P G for the miles involved. This past Inzane I had LOTS better fuel mileage and a little extra loot fer the trip.  If you set out NOT expecting real good fuel mileage and then you get better M P G-well than it's all good. As difficult as it is to do on these Valkyries cruising at 70 M P H or a tad less is where the good fuel mileage happens. You get into the 3300 3800 R P M range on the tach in 5th gear and hold that there-well YOU already KNOW dem dere results.  RIDE SAFE.

[rich_kildow]

120+ miles to a tank is typical for me...but I ride way harder than I should and usually do 72 or 73 on the way to work.  As others have said, heat, wind, speed, etc can really hit your mileage hard. 

We just found out that our 08 Chevy Equinox, which we usually got about 23 MPG in on the highway going 70 or 71, gets 30 MPG is we don't go over 67.  I would have never guessed and wouldn't believe it if I didn't see it myself.