40 mpg?--- UPDATE!

[JeremyP]

Well, here is yet another question:
Is 40 mpg (US) acceptable on my GS? and what can i do to raise it?

The bike is a 91 with a k&n and full yoshi exhaust and of course rejetted.
the filter was just "recharged" or cleaned, valve adjustment 2000 miles ago, carbs recently synced, and has the ngk iridium plugs, and tire pressure is fine.
I don't run the bike WOT 24/7 but i don't ride it like a grandma either.
The bike runs great: accelerates great (except it seems to bog down a bit under hard acceleration in 4th and 5th at 9k rpms), idles fine, and reaches an indicated 115mph no problem in a 2 mile stretch of open and empty highway.

Is there anything i can do to improve the mileage? is it time for a carb cleaning?

thanks for the help.

UPDATE: OK well i went on a gas saving campaign the last couple of days and was very disappointed! I took it really easy on the gs: kept the rpms under 6.5k and as low as possible without bogging, no quick acceleration's, perfect short warm up times, lots of coasting, top speed of 70mph, average speed of 50mph, 75% high way and 25% city, maybe 4 short trips and the rest were over 25 min.
and i still only squeezed 49mpg out of her!!!!!! 
Is this normal for my set up?
is there anything i can do?
should i just live with it and enjoy the ride?

thanks again!

[ohgood]

I'd bet on riding style would have plenty to do with MPG. Take it easy for a week and see if it improves. When all I did was commute, 50+ mpg wasn't difficult. Now I go for weekend blasts, and 40-45 is common. If I reign in the throttle, 50+ comes back easily.

[Cal Price]

With my GS I used to get about 56 to a UK gallon on short hops and around town and about 70 on my long trips. These figs are for a UK gallon so reduce by 20% for a US gallon.
US Gallon 128 fl oz
UK gallon 160 fl oz

This is because our pint glasses are 20 fl oz because we like beer so much!

[RobTheTyrant]

I've seen up to 60 on mine on while on morning commutes

[MadScientistMatt]

I've seen up to 60 on mine on while on morning commutes

Me too; mine seems to get anywhere from 50 to 60 depending on the weather.

[DarkStarr]

I average 50 on my 07

[gsJack]

I average approx 60 mpg all summer on my stock 02 GS and drop to as low as 50-55 mpg in the winter.  I'd consider less than 50 mpg unacceptable on a stock GS.  That's with a 110/80 front tire, would expect 2-3 mpg more with a standard 110/70 and got it on my 97 GS.

[The Antibody]

Well Jeremy, if you are aware that you can reach 115mph, then you shouldn't be suprised at 40mpg. Take it easy for a fill-up and see what you get.

Also, rejetting, high flow exhaust and air filter will lower your milage as well. It is probably riding style though. (as mentioned)

  -Anti 

[Kaizer]

Sigh...I hate you guys.  I can't get better than 40 mpg and now she is down in the 30s. will need to do more work on the gs. thanks.

[JeremyP]

read the update in the opening post

[erbilabuc]

get a better air filter. I get 42mpg out of my cbr 1000rr

[ohgood]

jeremyp -

you went from 40 mpg to 49 mpg ! that's a 23 % increase in fuel economy, and you didn't have to work at it !

do a few plug chops at different loads and see if you're overly rich somewhere.

also, if you're riding an E instead of an F, you'll not see those higher 50's mpg's, from what i've heard here.

congrats, you DID get better mpg's !

[JeremyP]

get a better air filter.

what?!?!?!?!? is there a better one then a freshly cleaned/recharged K&N?

congrats, you DID get better mpg's !

::sigh::  I guess youre right

[dgyver]

...
The bike is a 91 with a k&n and full yoshi exhaust and of course rejetted.
...

Is there anything i can do to improve the mileage?
...

Go back to stock, lose the free flow exhaust and high flow air filter. These require more fuel.

[qwertydude]

Sounds like you might have a rich spot in your midrange. When you rejetted you carbs, how much did you shim the needle by? I regularly get 63-65 mpg on my bone stock '06 F model. Hoping to get that figure up to 67 or so with my upcoming regear.

[JeremyP]

Sounds like you might have a rich spot in your midrange. When you rejetted you carbs, how much did you shim the needle by? I regularly get 63-65 mpg on my bone stock '06 F model. Hoping to get that figure up to 67 or so with my upcoming regear.

I got the bike with the filter exhaust and rejet done already, no idea what its insides look like. any way to tell if i have a rich spot while riding?

and dgyver, theres no way im going back to stock! i know it supposidly doesnt make that much different in performance but i definitely smoked a stock 04 gs off the line *maybe im just a better rider  )
I'd rather be a half a second quicker and a couple decibels louder with poor gas mileage then not be heard or not be able to get out of the way. 

[dgyver]

...
and dgyver, theres no way im going back to stock! i know it supposidly doesnt make that much different in performance but i definitely smoked a stock 04 gs off the line *maybe im just a better rider  )
I'd rather be a half a second quicker and a couple decibels louder with poor gas mileage then not be heard or not be able to get out of the way. 

They make a big difference in performance. The stock setup is very restrictive.

[ohgood]

I got the bike with the filter exhaust and rejet done already, no idea what its insides look like. any way to tell if i have a rich spot while riding?

jeremyp -

do a few plug chops at different loads and see if you're overly rich somewhere.

"plug chop" =

1) warm up the bike fully.

a) stop somewhere conducive to motorcycle stuff, and let it idle for a few moments.
b) ride it normally in the 'just off idle' range which means not hard acceleration.
c) ride it and give it HEAVY acceleration.
d) ride it and give it WOT.

IMMEDIATELY after a-d, pull in the clutch, and hit the ENGINE STOP switch, then coast into your previousely mentioned spot.

2) pull the plugs while the motor is still scorching hot (this is just for dramatic effect, and the fun of burnt fingers!)

3) read the plugs

using the a-d throttle positions and loads mentioned, you can get a really good idea of just how lean/rich your are at different rpm ranges.



I'd like to mention, with a 37/150 jetting, V&H, and K&N, I'm consistantly getting 45-55 mpg. Sure, there is a big difference between those numbers, but most of it has to do with my riding style. If I tried to squeeze mileage out of a gallon I'm pretty certain I could get 55-60+, even with the richer jetting. So much of it has to do with riding style, and the speed of the ride. Wind resistance is a HUGE factor. 55mph uses 10-25% less fuel than 75mph in cars, iirc.

The bike has a much lower drag coefficient, but the amount of resistance PER MILE changes drastically with more speed.

I'd bet if you found an older roadway that was conducive to 45-55 mph sustained cruising, you could get 65+ mpg, but then it wouldn't be much fun

[guitarking135]

If you wnat more gas mileage got back stock. EVERYTHING. all your preformance parts like with any bike car or truck do is suck gas. I get like 50s out of my stock but I hot rod it all the time. More air=more gas