Been thinking about this for a while. What do you think is the optimum speed for the gs to achieve the best MPG?? I know on cars the speed generally recomended is 55mph to get the best MPG. But that is too slow for the highways here in SA. You would get run over!

I have an 05 F with about 3k miles, I usually travel 70-75 mph on the highway, and noticed I get somewhere average 55 MPG. I did a search yesterday about MPG and found some people get 60+ MPG, How do yall do that? I don't ride like a bat out of hell and I am generally conservative on the throttle but still haven't seen more than 60 MPG.

your thoughts on this subject...

The way to get the best MPG is to keep a very consistent speed and limit weight and drag as much as possible.  Speeding up wastes more gas than anything else.  Maintaining a given speed will use the least amount of gas for the speed.

I'd guess that the GS gets the best mileage at 5K in 6th...  Not totally lugged, but not high RPMs...

I've found that if you maintain 50-60 MPH (80-100 KPH) in 6th gear you'll have the best chance at maintaining speed and experiencing low wind resistance.  I've hit 69 MPG with stock gearing in these conditions.

Superslabs drag my bikes MPG down into the low- to mid-50's.  Stop & go do the same at city speeds.

Anything between 5500-5700rpms, or about 65-67mph (indicated).

Oh man, you are all wrong, the optimum speed is 0. Then it gets infinite miles per gallon. (don't worry about it getting infinite gallons per mile)

How about an air speed of 0?

Ok, fine, I give, 5-6k is probably best.

My first two gas fill-ups in my break-in period came out to 64 MPG and 62.5 MPG.   I think keeping the RPM's below 5000 had a lot to do with it.  My previous '97 got in the 50's.   I think the fairing helps on the '05.  

As RVertigo stated, keeping the speed steady is probably your best bet.   Just like a car, avoid jackrabbit starts.   Overcoming inertia is where you'll burn the most gas.

Ok, I just calculated on the tank I filled up yesterday. I divided the 244 miles by the 4.25 gallons I put in and I got 57.41 MPG. Not to shabby, could be better though. The tank holds 5.3 gallons but when I filled up it didn't seem like I could put one more gallon in it. It was already up to the bottom of the neck.
I usually fill the tank up to the bottom of the neck while on the sidestand. Maybe I could get more while holding it upright. Oh well, next time...

57.41??!!! You should be freakin' ecstatic. After I did my rejet I got less than 40mpg. LESS THAN 40. I'm glad I went back to stock...

I average 43 MPG    on a 93 with 37k miles
its probably from all the stop and go driving here
I think it has stock jetting but I wouldn't know

Once it fills to the neck there may be room for another gallon. Stick some gas in and watch it go down. It seems to be a real pain though. Maybe a small hole in the side of the neck would be good.. Hmmm just have to do it without dropping nice metal parts into my gas/engine.

So Alpha do you think the performance gained was work the drop in MPG? :lol:  That is sad with a rejet.
Man my 02 Civic gets 37 mpg.

Quote from: Budrick320So Alpha do you think the performance gained was work the drop in MPG? :lol:  That is sad with a rejet.
Man my 02 Civic gets 37 mpg.

Performance gain? Ha! When I rejetted all I did was make it run really rich (thus killing my gas mileage). If I did a better rejet (dyno it at stock, figure out where it is rich and lean and change appropriately) I should be able to get better mileage, but I don't have the money to invest in that. That gigantic decrease in mileage was a significant factor in going back to stock jetting. My '98 Civic gets about 33 on the highway at 70mph, sometimes 36. It depends on how I drive it. I can get it as low as 24

i get anywhere from 55 to 60 mpg.  But i hit reserve and i have only ever put in 4 gallons at the max (normally 3.4-3.7), don't want to overfill her.  I know it is supposed to hold 5.3 but man i have never got close.  Of course as soon as i hit reserve i go to the station, is it possible there is that much on reserve :dunno:

PS : I always fill up on the centerstand and the book says to fill it to the bottom of the fill neck :dunno:

Quote from: natedawg120PS : I always fill up on the centerstand and the book says to fill it to the bottom of the fill neck :dunno:

Psh. The "book" is silly. I fill her up to the brim. Not enough to cause it to overflow, but there is definitely no wasted room in there. The only reason they say to the bottom of the neck is to ensure you don't fill it up and then park it. They give you leeway to deal with expanding gasses and whatnot.

yeah, i figured so much esp since i hit reserve way early.  But still i hit reserve anywhere from 160-180 depending on how i ride her and it only takes the 3.4-3.7 most of the time to fill her up.  So i figure what you are saying is right on the money.

What year model do you have? I used to go 160-180 on the '92 before having to switch over to reserve. Fill up receipts were somewhere in the vicinity of 3.6, IIRC.

When I first got my used 04 I got 70-75 MPG.  My commute is 65 miles one way, all backroads with very few stops.  I never went over 55 mph.  

Of course this only lasted about 2 weeks, now I am getting 58-62 MPG.  I am taking the highway more often, hitting speeds of 80-85 MPH.  

I've also been playing around at 9-10K rpm's when taking off.  It's pretty fun at the top end of the tach.  This bike can really get up and go if you push it!!!

crap.. my bike gets in the mid 30's, but i've set it up for all the stop and go shaZam! i do on my daily commute. I rejetted , piped and dropped a lunchbox in it. Put in Bob B's advancer and dropped a tooth on the front sprocket.  I wanted a little more snap off the line and if I take it out and tool around on the weekends I'll get more along the lines of mid to high 40's.

Jake

Highway use I usually see around 65ish but daily riding around 55-58 mpg.  Now that colder weather is here my mpg has went down due to letting it warm up for a couple minutes then the 1 minute trip to work.

A theoretical question needs a theoretical answer: ignoring all the important additional factors (wind, weight, road conditions, tire inflation...).

Assuming all those fixed conditions, from the engine-only point of view, the optimum speed is that where the gas is all burned properly (correct mixture): the "stechiometric mix", or air-fuel ratio about 14:1 (this number varies in the literature, also depending on the kind of gas used).  
Above this number the mixture is lean, and below is rich, and part of the gas is not burned and wasted.
Given the stock dyno run published by  dbarile (http://www.gstwins.com/forum/viewtopic.php?t=21789)

 
that makes the optimum engine speed around 5000 rpm, or 100km/h (63mph) on a stock bike.
Changing the front sprocket to 17 teeth it makes that speed go up to 106km/h (66mph).

Of course, you see that the same stechiometric value is obtained at 3900 rpm, around 80 km/h -50mph (or 85km/h -53mph- with a 17T sprocket).

Evidently, due to wind resistance, that makes: 50mph the optimum value.:

In practice I run 80% of the time around 4000-5000 rpm and I'm getting around 58mpg on a stock '03, with 17T sprocket.

I hope you all enjoyed this almost worthless theoretical exercise    

Riding style counts far more than all of these considerations...