ADVrider

Go Back   ADVrider > Bikes > GSpot > Parallel Universe
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-05-2015, 12:15 PM   #1
indylead OP
Adventurer
 
Joined: Mar 2014
Location: Toulouse, France
Oddometer: 17
Drop in mpg

I'm wondering if the collective knowledge here might shed some light on a potential issue I'm seeing on my 2011 F800GS.

I used to consistently get 150 miles range to the low fuel light coming on. This was the same for the first few years of ownership, over 35,000 miles. I generally use 98 grade unleaded, occasionally 95, from a range of suppliers in France. This would also be about the same for winter and summer riding.

Lately, and I mean the last 3-4 tanks, I'm only getting 115 miles, if that, until the fuel light comes on. Those three tanks have all been 98 grade unleaded, from different suppliers so I don't believe it is bad fuel.

Last service was at 36k miles, so about 2k miles and 6 months ago. The only 'tinkering' since then is that I had the steering bearing replaced, plus new chain and sprockets.

Anything obvious I can check to investigate this?

Thanks in advance.
indylead is online now   Reply With Quote
Old 01-05-2015, 12:39 PM   #2
Loutre
Cosmopolitan Adv
 
Loutre's Avatar
 
Joined: Nov 2010
Location: :o)
Oddometer: 3,767
J'ai le meme soucis depuis ~10000kms sur la mienne (elle a 65000 atm).
-> have the same issue with mine since about 10000kms.

Think that you'll need to reflash the ECU? It's the only thing that I can see that could change something (since in my case everything else is fine).
Loutre is offline   Reply With Quote
Old 01-05-2015, 12:50 PM   #3
jengel451
1 Cool MotherF#$cker
 
Joined: May 2011
Location: Eastern WA
Oddometer: 802
Are you just going by the light? Or are you truly getting worse mileage? Could be tank sending unit.
jengel451 is offline   Reply With Quote
Old 01-05-2015, 01:04 PM   #4
indylead OP
Adventurer
 
Joined: Mar 2014
Location: Toulouse, France
Oddometer: 17
Quote:
Originally Posted by jengel451 View Post
Are you just going by the light? Or are you truly getting worse mileage? Could be tank sending unit.
When I refuel, I fill to cut-out and reset the trip 1 counter. Low fuel light used to come on when trip 1 read 150 miles, now when it reads 115 miles.

Quantity of fuel going in at each fill up seems to be the same as before - I mean, if I fill up at that point I put in 12 litres or so, the same as always.

Quote:
Think that you'll need to reflash the ECU?
Is that something I can/want to do?
indylead is online now   Reply With Quote
Old 01-05-2015, 02:17 PM   #5
Loutre
Cosmopolitan Adv
 
Loutre's Avatar
 
Joined: Nov 2010
Location: :o)
Oddometer: 3,767
Quote:
Originally Posted by jengel451 View Post
Are you just going by the light? Or are you truly getting worse mileage? Could be tank sending unit.
No the bike uses more fuel for the same things (generally one liter more for me).

Quote:
Originally Posted by indylead View Post
Is that something I can/want to do?
Your dealer just connects your bike to their computer and does it. don't think you can do it with the GS911 (oh comon someone please tell me that you actually can so that I've got a good reason to buy one :o)
Loutre is offline   Reply With Quote
Old 01-05-2015, 03:23 PM   #6
jengel451
1 Cool MotherF#$cker
 
Joined: May 2011
Location: Eastern WA
Oddometer: 802
Quote:
Originally Posted by Loutre View Post
No the bike uses more fuel for the same things (generally one liter more for me).
That's actually good to know! I assumed it was a separate function so didn't put a lot of faith in it.
jengel451 is offline   Reply With Quote
Old 01-05-2015, 05:31 PM   #7
Bayner
Beastly Adventurer
 
Joined: Mar 2008
Location: Penticton, BC
Oddometer: 1,609
Did the same sprockets go on, or do the new ones have a different tooth count?
Bayner is offline   Reply With Quote
Old 01-05-2015, 08:15 PM   #8
BMW-K
F800GS FTW!
 
BMW-K's Avatar
 
Joined: Nov 2004
Location: Anaheim, CA
Oddometer: 1,480
Just getting a bit more frisky with the throttle? I managed to get 87 miles on tank once before getting the light to cry uncle...

If you are seriously concerned, go fill up a fresh tank and hit the freeway at an even 65 mph. Let us know the results.
__________________
2010 F800GS Anniversary - a return to Eden
2011 Yamaha WR250R, 2012 Ducati Monster
2007 R1200GS (Sold)

IBA # 20880. STFU and Ride.
BMW-K is offline   Reply With Quote
Old 01-06-2015, 02:53 AM   #9
Loutre
Cosmopolitan Adv
 
Loutre's Avatar
 
Joined: Nov 2010
Location: :o)
Oddometer: 3,767
Quote:
Originally Posted by BMW-K View Post
Just getting a bit more frisky with the throttle? I managed to get 87 miles on tank once before getting the light to cry uncle...

If you are seriously concerned, go fill up a fresh tank and hit the freeway at an even 65 mph. Let us know the results.
yup did that already to test it with previous values.

120km/h got me before a 5.4l now I'm at 6.2- 6.5l
90km/h got me 3.9l and now I'm at 4.6l
Loutre is offline   Reply With Quote
Old 01-06-2015, 06:12 AM   #10
Merlin32
Adventurer
 
Merlin32's Avatar
 
Joined: Nov 2014
Location: North East US
Oddometer: 72
Perhaps there's a small crack in the fuel line or tank and you're leaking fuel? Or sensor is fouled and you actually have more gas than you think.
Merlin32 is offline   Reply With Quote
Old 01-06-2015, 07:29 AM   #11
Loutre
Cosmopolitan Adv
 
Loutre's Avatar
 
Joined: Nov 2010
Location: :o)
Oddometer: 3,767
Quote:
Originally Posted by Merlin32 View Post
Perhaps there's a small crack in the fuel line or tank and you're leaking fuel? Or sensor is fouled and you actually have more gas than you think.
nope no more gaz in there since I refill everytime the same amout. I have one of the rare bikes that have a accurate fuel gauge
Loutre is offline   Reply With Quote
Old 01-06-2015, 07:31 AM   #12
jengel451
1 Cool MotherF#$cker
 
Joined: May 2011
Location: Eastern WA
Oddometer: 802
or.....god forbid they are adding Ethanol to your fuel.....that'll kill some mileage for sure.

Also, make sure your tires aren't low. I once road 20 miles on my bicycle and was really mad how out of shape I was, only to realize I was running low tires. I burned up my own gas pretty damn fast.
jengel451 is offline   Reply With Quote
Old 01-06-2015, 08:42 AM   #13
Loutre
Cosmopolitan Adv
 
Loutre's Avatar
 
Joined: Nov 2010
Location: :o)
Oddometer: 3,767
negative in both cases. That being said when I used Gas rated E10 I almost had no drop in mileage (about 10kms on the total range).

Go on with the bidding this shall be good
Loutre is offline   Reply With Quote
Old 01-06-2015, 08:53 AM   #14
jengel451
1 Cool MotherF#$cker
 
Joined: May 2011
Location: Eastern WA
Oddometer: 802
wobbly top case?
jengel451 is offline   Reply With Quote
Old 01-06-2015, 08:55 AM   #15
BMW-K
F800GS FTW!
 
BMW-K's Avatar
 
Joined: Nov 2004
Location: Anaheim, CA
Oddometer: 1,480
Quote:
Originally Posted by Loutre View Post
negative in both cases. That being said when I used Gas rated E10 I almost had no drop in mileage (about 10kms on the total range).

Go on with the bidding this shall be good
Did you add luggage, change the fairing, add crash bars, etc. or otherwise affect aerodynamics and/or weight? Riding more dirt and having fun with wheelspin?

I have a hard time believing anything actually is going wrong with that motor to cause a mileage drop like that. The Rotax twin is about as durable as they get. For me personally I found that my mileage has dropped as I became more comfortable with the bike...and therefore started hammering the throttle harder and harder. I average about 150 between fill ups but have gone as high as 200+.

You could check the following:
1. dragging brake pads
2. slipping clutch
3. burning oil (or adding oil between intervals could mean rings...)


Still, I suspect you shouldn't worry about it much. It's just one more thing to add to the BMW worry bead list that's probably muchado about nothing.
__________________
2010 F800GS Anniversary - a return to Eden
2011 Yamaha WR250R, 2012 Ducati Monster
2007 R1200GS (Sold)

IBA # 20880. STFU and Ride.
BMW-K is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 02:57 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2015