Fuel mileage

[nugz]

I know it's a topic that's been beat to death, but I have tried many things to improve it. I have a m/s batwing and travel mostly hiway at 75-80 mph and get 24-26 mpg. Does anyone have some info to get this into the 30's mpg.

Thanks,
Nugz
Sturgis SD

[Valker]

Slow down?

[rodeo1]

thats funny, but valkers right. these gold wing based motors are verysensitive to rpm. they do well below 3,000 rpm and lose it fast as you pass 3,000. i left delta utah one morning in the dark, because of the deer situation i was only running 45 mph for about 100 miles. got 50 mpg. got to salina ut. hit I-70 run up to 85 and dropped to 26 mpg.

[deadwood]

After I adjusted my valves and changed timing belts and plugs I think I picked up 2-3 MPG.
I assume it was all from the valve adjustment.

[Hazman]

thats funny, but valkers right. these gold wing based motors are verysensitive to rpm. they do well below 3,000 rpm and lose it fast as you pass 3,000. i left delta utah one morning in the dark, because of the deer situation i was only running 45 mph for about 100 miles. got 50 mpg. got to salina ut. hit I-70 run up to 85 and dropped to 26 mpg.

Looks like it goes to show you. The more sensible you drive the better mpg you get!

[fordmano]

Looks like it goes to show you. The more sensible you drive the better mpg you get!

And what fun is that? I know high fuel prices and all those nice go green ideas,,,, if I was only or primarily worried aboout MPG I would have picked up a Honda Rukus scooter and would never drive my Lovely FatLady or my big ARSE F350 4X4 super cab long bed dually diesel.


But then that's just me.

[sugerbear]

seems the older i get, the more i become a flower sniffer.

[Valkpilot]

I know it's a topic that's been beat to death, but I have tried many things to improve it. I have a m/s batwing and travel mostly hiway at 75-80 mph and get 24-26 mpg. Does anyone have some info to get this into the 30's mpg.

Thanks,
Nugz
Sturgis SD

Nugz,

That MPG isn't unusual at the speeds you're talking, but in my experience only gets that low when there's a strong head or cross wind.

If it is consistently that low, check the petcock.  Low MPG can be a symptom of impending failure.

Aside from that, I'd make sure the air cleaner was in good, clean condition; carbs are sync'd; no vacuum leaks from carb hoses and caps or intake boots.

Digging deeper, if the carbs have been rejetted, that could negatively affect mileage.

Hope this helps.

[Chiefy]

Nugz,

If it is consistently that low, check the petcock.  Low MPG can be a symptom of impending failure.

Hope this helps.

How does the petcock cause that?

[Daniel Meyer]

How does the petcock cause that?

Kind of counter-intuitive ain't it?

But it does...failing vacuum diaphragm restricts gas flow.

Not enough gas getting to all the carbs, throttle open more, carbs that ARE getting enough gas just dumping it down the cylinders, others running lean. PLUS the vacuum leak.

Seems strange that reduced gas flow would do it, but one of the first symptoms of a failed diaphragm in the petcock is reduced mileage. 

[Bone]

When my Petcock diaphragm failed it started fouling the spark plug. The gas was going down the vacuum line.

[Chiefy]

How does the petcock cause that?

Kind of counter-intuitive ain't it?

But it does...failing vacuum diaphragm restricts gas flow.

Not enough gas getting to all the carbs, throttle open more, carbs that ARE getting enough gas just dumping it down the cylinders, others running lean. PLUS the vacuum leak.

Seems strange that reduced gas flow would do it, but one of the first symptoms of a failed diaphragm in the petcock is reduced mileage. 

OIC   

[Valkpilot]

How does the petcock cause that?

Kind of counter-intuitive ain't it?

But it does...failing vacuum diaphragm restricts gas flow.

Not enough gas getting to all the carbs, throttle open more, carbs that ARE getting enough gas just dumping it down the cylinders, others running lean. PLUS the vacuum leak.

Seems strange that reduced gas flow would do it, but one of the first symptoms of a failed diaphragm in the petcock is reduced mileage. 

OIC   

I only know it because I learned the why from Daniel after I learned the what on the road.

In my case, I was running so rich on the right side that the plugs fouled to the point of not firing while the left bank was so lean they were white.

[Red Diamond]

When my Petcock diaphragm failed it started fouling the spark plug. The gas was going down the vacuum line.

If that is the case, then both your diaphragms failed. One failing won't get gas thru the vacuum tube.

[Beau57]

Been riding a Valk for about a month (weather permitting). Getting around 30 mpg with a large SwitchBlade windshield and cruising at 78-80mph with butt loads of wind. Guess I should feel lucky.

[NITRO]

Keep in mind that your mpg is related to your speed in terms of how much air the cycle has to "push" while you're moving. Try running at 4K rpms in 3rd (whatever speed that is) and you'll likely still have much better mpg than you would running 75 mph in 5th (approx. 4K rpm).

[eric in md]

had my i/s out of gas and reserve at 89 miles many times ,,, my bike is a gas hogggg  normal tank for me is 135  good luck aint no save gas for me

[Earl in Pensacola]

"eric":  You must really twist the wrist, because every IS I've encountered averaged 42MPG while "back-country-road-ridding". That would be about 60 MPH or anything under 3K RPMs.

[roboto65]

I regulary ride to my buddys house in Seagoville from Conroe it is 200 miles from my doorstep to his and I can do it sometimes depending on how much tailwind and my wrist without hitting reserve. Now sometimes I do hit reserve but thats if I do 80 mph the whole way 

[fudgie]

Dump alot of carb cleaner in it. I used the Gumout Regain and went from 32 to 36.
2 up loaded with b'wing at your speeds going west we still got 35 mpg.

[Ricky-D]

had my i/s out of gas and reserve at 89 miles many times ,,, my bike is a gas hogggg  normal tank for me is 135  good luck aint no save gas for me

There is something seriously wrong if that is the best you can get from an Interstate.

My first thought would be that there are larger main jets in the carburetors and also an air restriction.

***

[BIG--T]

thats funny, but valkers right. these gold wing based motors are verysensitive to rpm. they do well below 3,000 rpm and lose it fast as you pass 3,000. i left delta utah one morning in the dark, because of the deer situation i was only running 45 mph for about 100 miles. got 50 mpg. got to salina ut. hit I-70 run up to 85 and dropped to 26 mpg.

Looks like it goes to show you. The more sensible you drive the better mpg you get!

Yeah but....45 mph for 100 miles would be like a nightmare where I would wake up sweating!

[BIG--T]

"eric":  You must really twist the wrist, because every IS I've encountered averaged 42MPG while "back-country-road-ridding". That would be about 60 MPH or anything under 3K RPMs.

Just curious, at 42 mpg, why does an I/S get better gas mileage than Standards? Riding 2 up country riding below 60 and 35 mpg is all I get with or without windshield. I know the I/S is probably 50+ lbs heavier. Aerodynamics??  Most of the time it's 30 mpg because I do love to twist the wick

[MP]

"eric":  You must really twist the wrist, because every IS I've encountered averaged 42MPG while "back-country-road-ridding". That would be about 60 MPH or anything under 3K RPMs.

Just curious, at 42 mpg, why does an I/S get better gas mileage than Standards? Riding 2 up country riding below 60 and 35 mpg is all I get with or without windshield. I know the I/S is probably 50+ lbs heavier. Aerodynamics??  Most of the time it's 30 mpg because I do love to twist the wick

I think it is the aero.  The pods and the fairing are more aero than what the std has.

MP

[BIG--T]

"eric":  You must really twist the wrist, because every IS I've encountered averaged 42MPG while "back-country-road-ridding". That would be about 60 MPH or anything under 3K RPMs.

Just curious, at 42 mpg, why does an I/S get better gas mileage than Standards? Riding 2 up country riding below 60 and 35 mpg is all I get with or without windshield. I know the I/S is probably 50+ lbs heavier. Aerodynamics??  Most of the time it's 30 mpg because I do love to twist the wick

I think it is the aero.  The pods and the fairing are more aero than what the std has.

MP

That could be, but I just found out that the I/S is 91.8 lbs heavier!

[X Ring]

"eric":  You must really twist the wrist, because every IS I've encountered averaged 42MPG while "back-country-road-ridding". That would be about 60 MPH or anything under 3K RPMs.

Just curious, at 42 mpg, why does an I/S get better gas mileage than Standards? Riding 2 up country riding below 60 and 35 mpg is all I get with or without windshield. I know the I/S is probably 50+ lbs heavier. Aerodynamics??  Most of the time it's 30 mpg because I do love to twist the wick

I think it is the aero.  The pods and the fairing are more aero than what the std has.

MP

That could be, but I just found out that the I/S is 91.8 lbs heavier!

And you're surprised how?  It's not like the fairing, pods, bags and trunk are made of air.  The I/S fairing and pods provide a less turbulent air flow than the Standard/Tourers have.

Marty

[Kymbo]

On average I get 37 mpg no matter how I ride on the standard

[R J]

I know it's a topic that's been beat to death, but I have tried many things to improve it. I have a m/s batwing and travel mostly hiway at 75-80 mph and get 24-26 mpg. Does anyone have some info to get this into the 30's mpg.

Thanks,
Nugz
Sturgis SD

If you bought this bike to get gas mileage, you are barking up the wrong tree.

At the speeds you are running, there is no way in hell you will get 30 mpg.

Any RPM over 3,000, kills your MPG.

If you want mileage, drop the RPM's to below 3,000, and preferably around 2,700, with no rabbit stops or starts.

[BIG--T]

"eric":  You must really twist the wrist, because every IS I've encountered averaged 42MPG while "back-country-road-ridding". That would be about 60 MPH or anything under 3K RPMs.

Just curious, at 42 mpg, why does an I/S get better gas mileage than Standards? Riding 2 up country riding below 60 and 35 mpg is all I get with or without windshield. I know the I/S is probably 50+ lbs heavier. Aerodynamics??  Most of the time it's 30 mpg because I do love to twist the wick

I think it is the aero.  The pods and the fairing are more aero than what the std has.

MP

That could be, but I just found out that the I/S is 91.8 lbs heavier!

And you're surprised how?  It's not like the fairing, pods, bags and trunk are made of air.  The I/S fairing and pods provide a less turbulent air flow than the Standard/Tourers have.

Marty

So Marty are you saying if I put on a fairing, pods, hard bags, trunk and more adding almost 100 lbs, I should get 42 mpg or more  riding normally? I understand aerodynamics, but wouldn't adding extra weight to a bike cost mileage? Like a 120 lb rider vs 2 300 lb riders = 600 lbs.

[BIG--T]

On average I get 37 mpg no matter how I ride on the standard

Kymbo, Please let me in on your secret! I would love to get 37 mpg running WOT or under 3000 rpm!

[BIG--T]

I'm gonna try what Rodeo1 did and see what I get just see what I get for the heck of it. But if I even come close to 50 mpg I'll let ya'll know! Maintaining 45 mph for 100 miles will me hard!!

[Hoser]

Flower sniffin, no wind, 2 lane blacktop at 3000 rpm or less = 40mpg
4 lane I-70 75+ into the wind = 30mpg
Every thing is else is in between.  Good enough for me.  Hoser 

[X Ring]

Don't forget the I/S has different engine management.  The Ignition Control Module and carb springs are different on the I/S than on the Standard/Tourers.

Marty

[BIG--T]

Don't forget the I/S has different engine management.  The Ignition Control Module and carb springs are different on the I/S than on the Standard/Tourers.

Marty

I forgot about the ICM and the springs! If I do that mod, how much will that increase my mpg?

Thanks, Tony

[BIG--T]

Flower sniffin, no wind, 2 lane blacktop at 3000 rpm or less = 40mpg
4 lane I-70 75+ into the wind = 30mpg
Every thing is else is in between.  Good enough for me.  Hoser 

I think I've been flower sniffin too much cause I've been sneezing my head off!! 
Thanks for that smelly information...now I won't have to torture myself trying to run 45 mph for 100 miles!

[Redline +]

Don't forget the I/S has different engine management.  The Ignition Control Module and carb springs are different on the I/S than on the Standard/Tourers.

Marty

I forgot about the ICM and the springs! If I do that mod, how much will that increase my mpg?

Thanks, Tony

I just installed the IS ICM and carb springs in my 2002. Forget about a mpg increase...because now it's even more fun to twist the throttle!

Redline 

[BIG--T]

Don't forget the I/S has different engine management.  The Ignition Control Module and carb springs are different on the I/S than on the Standard/Tourers.

Marty

I forgot about the ICM and the springs! If I do that mod, how much will that increase my mpg?

Thanks, Tony

I just installed the IS ICM and carb springs in my 2002. Forget about a mpg increase...because now it's even more fun to twist the throttle!

Redline 

Wow  how many more ponies did you pick up  and is it all across the board, meaning low and high end? So you got the ICM and just plugged in ...no radio shack stuff mod?
Thanks

[eric in md]

had my i/s out of gas and reserve at 89 miles many times ,,, my bike is a gas hogggg  normal tank for me is 135  good luck aint no save gas for me

There is something seriously wrong if that is the best you can get from an Interstate.

My first thought would be that there are larger main jets in the carburetors and also an air restriction.

***

ricky its stock stock i bought it with .2  on the speed o , now  the rest of the story . on any good day i can get 180 - 200 miles out of tank . mostly 135 150 range . when i got 89 miles out of a tank i was pulling a trailer 500lbs , headwind , sideways, it was 115 degrees going across rt 90 south dakota headed to sturgis .  i was only running like 110- 115 mph  the whole tank i did this for 300 miles i think that was one of my top worst days riding i have done.. Coming home from daytona this year 989 miles 12 1/2 hours average tank was 135 -150 man that was a good ride 3 of us hammer down  .      anybody want to ride across country with us were leaving july 16 for two weeks,  all out west going to be a rock and roll trip part 3 o yea

[GJS]

My 99IS consistently gets 35-37 commuting to and from work, about 80km (50miles) roundtrip.
Three years on a long trip with my wife (2up), we kept to the side roads and mostly stayed between 45-65mph. I was stunned to get the best milage ever. 39-40MPG, fully loaded, 2up.

I keep the phat lady tuned and use synthectic fluids.  I love this bike!

Glenn

[Redline +]

Don't forget the I/S has different engine management.  The Ignition Control Module and carb springs are different on the I/S than on the Standard/Tourers.

Marty

I forgot about the ICM and the springs! If I do that mod, how much will that increase my mpg?

Thanks, Tony

I just installed the IS ICM and carb springs in my 2002. Forget about a mpg increase...because now it's even more fun to twist the throttle!

Redline 

Wow  how many more ponies did you pick up  and is it all across the board, meaning low and high end? So you got the ICM and just plugged in ...no radio shack stuff mod?
Thanks

I don't know if there is any HP increase...but the IS springs and ICM increase the performance on the bottom end. It's all plug and play.

Redline