GSX1400 Owners .org

Technically Speaking => Engine & Gearbox => Topic started by: AndyB on Friday, 06 November 2020, 06:12 PM

Title: Fuel consumption
Post by: AndyB on Friday, 06 November 2020, 06:12 PM
Hi fellas,
2003 K3...PCIII , full Akro system,  standard motor apart from that I believe.
Now I know the fuel gauge is more of a rough guide,but brim the tank & the gauge reads full.....doesn't stay there for very long 20 or 30 miles of 80/90mph..maybe a short look at 130 mph.. :whistling:.and the fuel gauge is down to 2 bars flickering onto 1 bar...so back into the garage to fuel up.....I forgot to look in the tank to see how much was left in but it took £15....so either I'm using alot of fuel or my fuel gauge is takin the piss....a couple of questions....how much to fill the tank from a true fuel light indication...and how much range is left in the tank once you have a flashing light
Title: Re: Fuel consumption
Post by: KiwiCol on Friday, 06 November 2020, 06:15 PM
6L when the last bar comes on & 1.75L when the fuel symbol is flashing as well as the last bar.

Have you done the tank mod where you can brim it easily & get 24 - 25L?    #2 Philips is all ya need.

https://gsx1400owners.org/forum/index.php?topic=1790.0
Title: Re: Fuel consumption
Post by: AndyB on Friday, 06 November 2020, 06:31 PM
Firstly...apologises for putting a fueling issue in the engine section....
KiwiCol...No mate I've not done that but what a great mod...I,ll have a shot of that....and cheers for the capacity information.....1.7 Ltrs is a small amount...guess I,ll have to keep an eye on my levels .....I've not had this one long...so I'm just caning the crap out of it every chance I get... :happy1:..once I calm down I,ll get an idea of how much I'm actually using at a steady pace.....but it's just soooooo hard not to let it go
Title: Re: Fuel consumption
Post by: grog on Friday, 06 November 2020, 06:46 PM
At those speeds Mate, just keep filling.
Title: Re: Fuel consumption
Post by: Hooli on Friday, 06 November 2020, 07:31 PM
I'd take a note of mileage done & litres put in then work out your MPG. When my K2 was younger with the same mods I used to get over 40mpg unless I did the whole ride in 2nd! ridden properly I'd get about 180miles to reserve (pump symbol flashing & one bar left).

Mines running wrong at the moment & drinking like Oliver Reed, I've not found why yet.
Title: Re: Fuel consumption
Post by: Irish in Oz on Friday, 06 November 2020, 07:41 PM
Does Oliver Reed still drink.
Title: Re: Fuel consumption
Post by: Hooli on Friday, 06 November 2020, 07:49 PM
Not for the last 21 years...
Title: Re: Fuel consumption
Post by: DP1400 on Saturday, 07 November 2020, 06:47 AM
AndyB - I`ll get 170-180 miles from full tank to `reserve` on my K3 - and thats `not hanging around` two-up. I appreciate this doesn`t answer either of your questions directly, but I think its worth mentioning as a guide, given that riding styles and conditions vary. :cheers:
Title: Re: Fuel consumption
Post by: AndyB on Saturday, 07 November 2020, 09:01 AM
Cheers for the info fellas...its gonna be dry tomorrow, so I,ll brim it & try to contain myself to see how much its using......but that will go straight out the window if something juicy want to play :happy1:
I,ll also take and post a few pictures if I end up somewhere other than in the back of a traffic car.... :rofl2:
Title: Re: Fuel consumption
Post by: DP1400 on Saturday, 07 November 2020, 07:49 PM
Play nicely.......! :grin:
Title: Re: Fuel consumption
Post by: imweirdimnotsocial21 on Sunday, 09 August 2026, 06:26 AM
Hi y'all reviving a really old topic here, but I am just wondering what is y'alls fuel consumption on the GSX1400.

Mine, K2, with 58,363km on the clock, does on average (includes really spirited riding, track use, and highway) 8.1L/100km.

Here's the excel data as a proof! :D

Fuel_Consumtion_Aug_2026.jpg


P.S.

I saw a post about increasing the tank size, for now, I am assuming that my tank is at 22L during these calculations, but I bet it will be quite useful to get +2.1L.

Cheers everyone!


Title: Re: Fuel consumption
Post by: Hooli on Sunday, 09 August 2026, 07:11 AM
I normally get 47-48mpg (UK gallon, 4.54l) out of mine and the same for others I know.
Title: Re: Fuel consumption
Post by: imweirdimnotsocial21 on Sunday, 09 August 2026, 08:16 AM
Quote from: Hooli on Sunday, 09 August  2026, 07:11 AMI normally get 47-48mpg (UK gallon, 4.54l) out of mine and the same for others I know.


No way you're below 6L/100km mate. That is simply impossible ! We're talking 20 year old bikes with no interest at all for efficiency. I'm really sorry but I find this really hard to believe!!!!

Do you have any data to support this?

Title: Re: Fuel consumption
Post by: Hooli on Sunday, 09 August 2026, 01:47 PM
Quote from: imweirdimnotsocial21 on Sunday, 09 August  2026, 08:16 AM
Quote from: Hooli on Sunday, 09 August  2026, 07:11 AMI normally get 47-48mpg (UK gallon, 4.54l) out of mine and the same for others I know.


No way you're below 6L/100km mate. That is simply impossible ! We're talking 20 year old bikes with no interest at all for efficiency. I'm really sorry but I find this really hard to believe!!!!

Do you have any data to support this?



Does over 180,000 mile of riding on 14s I've owned not count then?

They'll do 53-54mpg ridden gently, but it's not often I ride like that.
Title: Re: Fuel consumption
Post by: grog on Sunday, 09 August 2026, 02:01 PM
Haven't checked mine for a while but it's always been around the same.Best ever was 420ks on a tank, loaded and Wife on back. Usually 360-400 normal riding. Think around 50mpg.
Title: Re: Fuel consumption
Post by: Mr Gee on Sunday, 09 August 2026, 03:43 PM
Hooli is spot on.  :onya:

48 is my average and 55 is attainable ridden sedately.  :boogie2:

Not that it happens too often.  :happy1:
Title: Re: Fuel consumption
Post by: Mick_J on Sunday, 09 August 2026, 06:02 PM
I get around 50 miles to the gallon and if I take it easy it can get up to 55.
Title: Re: Fuel consumption
Post by: Hooli on Sunday, 09 August 2026, 06:17 PM
Quote from: imweirdimnotsocial21 on Sunday, 09 August  2026, 08:16 AM
Quote from: Hooli on Sunday, 09 August  2026, 07:11 AMI normally get 47-48mpg (UK gallon, 4.54l) out of mine and the same for others I know.


No way you're below 6L/100km mate. That is simply impossible ! We're talking 20 year old bikes with no interest at all for efficiency. I'm really sorry but I find this really hard to believe!!!!

Do you have any data to support this?



Btw if yours is always terrible, check the oil temp sensor. They can fail to high resistance which causes a very rich mixture. When mine went I was getting 27mpg or so ridden the same as normal.
This doesn't cause a warning code or affect the fast idle.
Title: Re: Fuel consumption
Post by: imweirdimnotsocial21 on Sunday, 09 August 2026, 06:27 PM
Thanks yall for the reply! I'm flabbergasted to the core.


The only thing I can imagine affecting the consumption, other than riding style, cause I know you all ride calmer than me, is also the fuel itself and the weather conditions.

I believe this group consists mostly of people living in Australia and New Zealand right? Probably you guys have some sort of different fuel than what we have in EU.

And also, probably your bikes don't see past 4K RPM, because there's no other way on this engine to consume less than 6L/100km.

In my case you have the excel and you can see all the data.
Title: Re: Fuel consumption
Post by: Tony Nitrous on Sunday, 09 August 2026, 06:28 PM
I have several bikes that if I'm not giving them big licks they'll return between 18 and 20K's per ltr. Some are older and more powerful than my 1400 and return the same numbers.
Title: Re: Fuel consumption
Post by: Eric GSX1400K3 on Sunday, 09 August 2026, 06:34 PM
Usually I get 5.4-5.5l/100km and she gets to see the high end of the rev range. K&N air filter and full Akrapovic.  2003 Model with 55000km on the odo.

Your 8l/100km seems very high.
Title: Re: Fuel consumption
Post by: GSXKING on Sunday, 09 August 2026, 06:51 PM
Mine is 2001 from new with titanium headers, stainless muffler. K&N air filter. No other aids re timing etc.
it's always ridden aggressively.
Bike has traveled 185,000+kms as best as I can figure it's using 6+ litres/100kmh. :cheers:

I never even considered frugality 💰💰
Title: Re: Fuel consumption
Post by: grog on Sunday, 09 August 2026, 07:17 PM
I reckon more members northern hemisphere.We tell it as it is, no bloody proof needed. You ride on race track then worry about fuel consumption WTF.Youve asked,been told and still disagree🤷🏼
Title: Re: Fuel consumption
Post by: KiwiCol on Sunday, 09 August 2026, 07:56 PM
Quote from: imweirdimnotsocial21 on Sunday, 09 August  2026, 08:16 AM
Quote from: Hooli on Sunday, 09 August  2026, 07:11 AMI normally get 47-48mpg (UK gallon, 4.54l) out of mine and the same for others I know.


No way you're below 6L/100km mate. That is simply impossible ! We're talking 20 year old bikes with no interest at all for efficiency. I'm really sorry but I find this really hard to believe!!!!

Do you have any data to support this?




Well, hard as it may be to believe, it's true. I went & dug out my old fuel use files for the Black K6.  See below. Average fuel use was 5.99L/100k.  Oh & the 24L tank capacity is achieved by enlarging the filler vent with a phillips screwdriver.

The DRD Adjusted column is because the speedo reads incorrect, think mine was 10.5% out or something, was a long time ago I set that up.  The odo reads slow & this column adjusts for the discrepancy in distance covered. 

And you're right Grog, there are way more members from the top half than the bottom half.  But what we lack in numbers, we make up for in quality . . .   :cheers:


Averages.jpg

Title: Re: Fuel consumption
Post by: Tony Nitrous on Sunday, 09 August 2026, 08:21 PM
Quote from: imweirdimnotsocial21 on Sunday, 09 August  2026, 06:27 PMAnd also, probably your bikes don't see past 4K RPM, because there's no other way on this engine to consume less than 6L/100km.


My tank holds close to 24 ltrs, it has the filler neck mod.
I've done close to 400K's on one tank.

(Aftermarket Speedo / dash checked multiple times, I'd consider it more accurate than the factory original)

If you think folk on here don't go over 4,000 revs you're away with the fairies.
Title: Re: Fuel consumption
Post by: imweirdimnotsocial21 on Sunday, 09 August 2026, 08:30 PM
Quote from: KiwiCol on Sunday, 09 August  2026, 07:56 PM
Quote from: imweirdimnotsocial21 on Sunday, 09 August  2026, 08:16 AM
Quote from: Hooli on Sunday, 09 August  2026, 07:11 AMI normally get 47-48mpg (UK gallon, 4.54l) out of mine and the same for others I know.


No way you're below 6L/100km mate. That is simply impossible ! We're talking 20 year old bikes with no interest at all for efficiency. I'm really sorry but I find this really hard to believe!!!!

Do you have any data to support this?




Well, hard as it may be to believe, it's true. I went & dug out my old fuel use files for the Black K6.  See below. Average fuel use was 5.99L/100k.  Oh & the 24L tank capacity is achieved by enlarging the filler vent with a phillips screwdriver.

The DRD Adjusted column is because the speedo reads incorrect, think mine was 10.5% out or something, was a long time ago I set that up.  The odo reads slow & this column adjusts for the discrepancy in distance covered. 

And you're right Grog, there are way more members from the top half than the bottom half.  But what we lack in numbers, we make up for in quality . . .   :cheers:


Averages.jpg





That is awesome mate! Well documented and well ridden!

I guess I need to double check my vacuum lines from the TBs to the MAP sensor, as my deviation can be coming from there.

This could be the numbers I could look up to. Do you think fuel mix deteriroated significantly since 2017 in your area?
Here in Poland, we have the 95/E10 (up to 10% ethanol mix) and then 98/E5 (up to 5% mix) as premium. I'm filling up with 98 octane and I pay the premium for the hopes of a smoother combustion as the bike was never mapped to run on fuel mix with ethanol and works on an open loop setup without O2 systems.

What do you reckon?
Title: Re: Fuel consumption
Post by: MickyJB on Sunday, 09 August 2026, 08:51 PM
I keep fuel figures for all my bikes & Car

GSX 1400 here
Title: Re: Fuel consumption
Post by: Tony Nitrous on Sunday, 09 August 2026, 08:52 PM
Where I live there is no 95 that more built up areas get.
My nearest servo only sells, Diesel, 91 and 98.

95 and E10 are available elsewhere but I can't rely on finding them near me.

My GSX1400 and Gen-2 Busa are dyno'd and tuned / mapped with BP98.

As I can't get 95 it's that or 91. 

Bikes like my previous H2 and current Gen-3 Busa don't recommend 91.

Zero issues with fuel.
Title: Re: Fuel consumption
Post by: Hooli on Sunday, 09 August 2026, 09:39 PM
I run 97/98/99 E5 in my bikes, the octane depends on the brand. Knock 10% off the economy if I have to use E10 and they don't run as nice.

Like I said before, check your oil temp sensor. That's the main mixture control on these old girls. There's values to test again the workshop manual you can download from here. I've seen two personally that went high resistance, the bikes ran ok but drank like Oliver Reed.
Title: Re: Fuel consumption
Post by: imweirdimnotsocial21 on Sunday, 09 August 2026, 10:44 PM
Quote from: Hooli on Sunday, 09 August  2026, 09:39 PMI run 97/98/99 E5 in my bikes, the octane depends on the brand. Knock 10% off the economy if I have to use E10 and they don't run as nice.

Like I said before, check your oil temp sensor. That's the main mixture control on these old girls. There's values to test again the workshop manual you can download from here. I've seen two personally that went high resistance, the bikes ran ok but drank like Oliver Reed.

Great advice mate. I'll do that. Will check cold and hot resistances as per manual and will update here.

Cheers!