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Main Area => General GS500 Discussion => Topic started by: bombadillo on June 18, 2007, 10:27:13 PM

Title: Well, scratching my head about gas mileage again.
Post by: bombadillo on June 18, 2007, 10:27:13 PM
I just had the valves redone, put back to specs, its bone stock with a foam filter and stock exhaust.  I have the bottom tube that lets out the water that can build up in the bike taken off and maybe its letting too much air in or something so I think its time to plug it.  I had everything checked through and adjusted, adjusted chain, adjusted clutch, and riding it pretty hard on an in-town 100 mile jaunt, its getting exactly 30mpg.  I figured 40 would be low, but I just got 50 mpg on the highway, so I don't know what to think about this.  I get 50-55 mpg highway and 30 in the city?????? What do you guys think is going on.  What do you need to know more to diagnose it.  Brand new plugs, stock afr, stock jets, cleaned carbs, adjusted valves, foam filter, CA smog still connected.  Why the low gas mileage?
Title: Re: Well, scratching my head about gas mileage again.
Post by: nastynate6695 on June 18, 2007, 10:43:28 PM
hows your gear ratio??
Title: Re: Well, scratching my head about gas mileage again.
Post by: bombadillo on June 18, 2007, 10:58:05 PM
stock for now, I'm getting a 15t for the front and a new did roller chain within the week.
Title: Re: Well, scratching my head about gas mileage again.
Post by: bombadillo on June 19, 2007, 10:00:01 AM
nobody???
Title: Re: Well, scratching my head about gas mileage again.
Post by: The Buddha on June 19, 2007, 10:18:02 AM
50 highway is good. But you prolly flogging it in city. Time to take it easy there.
Cool.
Srinath.
Title: Re: Well, scratching my head about gas mileage again.
Post by: Chuck on June 19, 2007, 11:00:59 AM
Could be your idle circuit in your carbs is hosed, like running rich or something.  That wouldn't affect you on the highway.  Or your city traffic is really bad.  I've never done a full tank of fuel in-city, so I wouldn't know if 30 is normal or not.
Title: Re: Well, scratching my head about gas mileage again.
Post by: werase643 on June 19, 2007, 11:54:27 AM
I used to get about 15 mpg
.....
....
oh yeah, round slides and WFO
never mind, nothing to see here.... :icon_mrgreen:
Title: Re: Well, scratching my head about gas mileage again.
Post by: scratch on June 19, 2007, 12:10:58 PM
Are you doing a lot of stop-and-go?

How long are you sitting at stoplights?

Do you split lanes?

Check compression, using the thumb-over-the-sparkplug-hole method, if it doesn't blow your thumb off the hole, then squirt some oil in there and try again.  If is does the second time, it's your rings.
Title: Re: Well, scratching my head about gas mileage again.
Post by: bombadillo on June 19, 2007, 08:57:10 PM
I don't sit at traffic that long.  I do go through a full tank in all city though.  I rarely go on the highway as we're in a rural place and its only about 50k with nobody around us forever.  As far as compression, it feels great, I don't think thats the problem.  I am still timid about splitting lanes as I am new to bikes in general and don't know the proper etiquette of lane splitting.  I am flogging on it through first 2nd and third though as srinath said.  I may just need to ease up off the throttle and stop shifting at 9k and shift at 4 or 5k instead.
Title: Re: Well, scratching my head about gas mileage again.
Post by: FearedGS500 on June 19, 2007, 09:08:33 PM
thats where your problem is . when i first got my gs for the first . 2k i never really got above 8k . i shifted about 6k or so and on the high way at one point i was getting about 70 mpg on the high way and about 50 or 60 in the city . now that i ride the hell out of it . it has droped i get about 55-60 mpg on the high way and a little less in the city . when you stay on it at 9k your really eating up that gas :)
Title: Re: Well, scratching my head about gas mileage again.
Post by: Dom on June 20, 2007, 10:58:25 PM
If I did my math right I got over 70mpg once on the freeway going around 85mph with overinflated tires, ignition advance, stage 3.  May have had a slight tailwind.  :laugh:

Yes, that was me bragging.
Title: Re: Well, scratching my head about gas mileage again.
Post by: Crucialval on June 21, 2007, 06:26:30 AM
I only get 40 mpg, but I never ride the highway only mountain roads. I normaly ride it around 6k-10k all the time so I guess thats why my bike sucks gas. It dosn't seem to run as good at lower RPM's or maybe I'm just a power junkie on a power deprived bike.
Title: Re: Well, scratching my head about gas mileage again.
Post by: bombadillo on June 21, 2007, 08:38:09 AM
I know tire pressure makes a difference, but does the chain make that big of a difference for rolling resistance???
Title: Re: Well, scratching my head about gas mileage again.
Post by: scratch on June 21, 2007, 11:00:11 AM
Sure can!
Title: Re: Well, scratching my head about gas mileage again.
Post by: AcidReign on June 21, 2007, 02:21:35 PM
My last two tanks of gas were 49 MPG and 52 MPG respectively.It's kinda cool when I see Honda Civics driving around and think "Kaching, Kaching, Kaching" and see dollar signs $$$ comming from the exhaust pipe. :D
Title: Re: Well, scratching my head about gas mileage again.
Post by: pbureau69 on June 21, 2007, 03:01:11 PM
my log shows on my 05 F model,

date      -   MPG
05.11.07 - 55.625
05.15.07 - 56.568
05.20.07 - 55.502
05.23.07 - 52.934
06.03.07 - 50.130 <- got spark plug and oil changed.
06.06.07 - 59.875 (see the difference here )
06.13.07 - 56.611

now I ride 118 miles a day to work/home round trip I ride 90% of that on highways average speeds of 70-80.

no idea if this is normal, but seems consistant ...

PS: never seen 70mpg on the GS.

PPS : the GS has 13,000 miles on it.

Title: Re: Well, scratching my head about gas mileage again.
Post by: 97dime on June 21, 2007, 06:31:49 PM
i get anywhere from 50-60 mpg (usually closer to 50).  i ride mostly 2 lane back roads at 70-80mph, 70 on the interstate(too many cops).  20 +/- miles one way to/from work. about 15 miles 2 lane, 5 on interstate.