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Main Area => General GS500 Discussion => Topic started by: pingpong on March 14, 2007, 02:37:59 AM

Title: OK this MPG is just getting pretty ridiculous
Post by: pingpong on March 14, 2007, 02:37:59 AM
So for my last five or six tanks of gas, I've been getting roughly ~25MPG. No matter how hard I ride it, there shouldn't be any possible way I could get something that low, right? I've been using the same station (gas station at the corner of MLK and Hearst in Berkeley, for anyone that cares), and the same pump (pump number 2). Always straddle the bike to keep it centered, and fill it till it reaches the bottom of the neck of the tank. My rides usually consist of short 5-10 mile jaunts, with about a 30 second warmup with choke at 2500RPM, then off once I get going. Idles anywhere between 1100-1400 depending on outside temp, cruise at around 5000RPM, and shift before 8000RPM. Rejetted, aftermarket exhaust, and down one tooth on the sprocket up front, but even with ALL these things combined, I shouldn't be seeing only 25MPG, right? I'm getting worse mileage in the city than my Corolla right now, so what the heck could be going one? I did one tank on the highway (6th gear 6500RPM most of the way), ended up getting about 150 miles off of 4.3 gallons (~35MPG). WTF  :dunno_white:

In any case, does anyone have any ideas as to what could cause this? I don't think there's a fuel leak, and my plugs aren't blackened so I don't think I'm running rich. Where could all that gas be going?
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: bettingpython on March 14, 2007, 04:05:52 AM
You are using it :cookoo:

MPG ratings are way over rated, best mileage I ever got on the GS was around 32mpg on the highway.

Your Corolla may get better mileage than my bike but my bike gets better mileage than my truck and its wicked fun
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: PuddleJumper on March 14, 2007, 05:32:51 AM
I have an '04 model.
Factory stock. On the interstate, I get 52 MPG consistently.
On a easy backroad ride, I can get almost 63 MPG.

I don't think I'll be rejeting it anytime soon. :thumb:
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: scottpA_GS on March 14, 2007, 07:50:09 AM
I have a 95 and get about 55-60 MPG on average  :thumb:
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: jsamaniego on March 14, 2007, 08:17:16 AM
While MPG depends lots on your riding style, 25MPG is way too low... I'd check the carbs float level, air filter, spark plugs and ... well I guess that if a valve was not closing correctly (check shims) that would lower the power and decrease mileage as well.
Finally, the advance in the spark timing could also affect it, but I assume it's all OK (no pinging...)

How does the somke coming out of the axhaust smell like?  If you cover it with a clean kleenex (paper towel...) does it make it dirty with black dust?

... my 2 cents... I also get consistently over 55 MPG (US gallons!) :cheers:
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: FearedGS500 on March 14, 2007, 08:32:41 AM
i get about 180 off of my reg. tank :)  i use to get about 200 .. but i'v changed my riding style since . i pretty much ride it to 9.5k every gear (well .. not 6th but )  you do have a rejet that will eat more gas

**edit** mines also a stock 05)
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: Trwhouse on March 14, 2007, 08:47:07 AM
Hi there,
Yes, your mileage is way off.
I, too, get 55-65 mpg consistently, with a mix of city and highway riding.
Time to clean and check the carbs over and see what's up on your bike.
Good luck, and keep asking for help here. There are plenty of us who can help you resolve this.
Best wishes,
Todd
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: jazerr on March 14, 2007, 09:09:07 AM
Also, in this motor, I've learned that the condition of your oil makes a HUGE difference. I got the bike right after an oil change and was getting about 55-60mpg. But after 3k miles I was getting about 43mpg.

I ALWAYS shift at 2/3 of redline. So, redline is 10.5k, and I shift around 7k-78k.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: Alphamazing on March 14, 2007, 10:46:54 AM
The only time I got that type of fuel mileage was when I had a fuel leak. Check your fuel lines and make sure they aren't cut and cracked.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: RVertigo on March 14, 2007, 11:22:12 AM
I have 14t Sprocket on the front...  Long warm-ups, and a 4.5 mile commute each direction...  I'm getting terrible gas mileage....   And it's still around 40 MPG.

I agree that something is wrong.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: krypto35 on March 14, 2007, 11:25:06 AM
I agree, look for SOME kind of leak - I recently started a Fuel Mileage thread and got TONS of great responses (it has since died out... come on guys!) But even with mod-ed bikes, like mine, mileage didn't really fall below 45mpg.  I have yet to confirm mileage on my '95 with the WORKS when it comes to DIY mods, but I sure hope it doesn't turn out to be comparable to my el camino - lets pray you find something wrong!  Let us know for sure - there's gotto be a leak or someone is jacking your fuel at night! - any neighbor kids been cruising on their mopeds more than usual?!?! :icon_twisted:  at 25mpg, u'd think ur carbs would be flooding the engine out.  keep us posted
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: pingpong on March 14, 2007, 12:30:53 PM
Think it could be the valves that need adjusting? it's strange, the bike feels normal and runs smooth, except it's a gas-whore. I haven't noticed any fuel running down the outside of the lines or any other pooling anywhere. Guess I'll be doing an oil change, carbs, and a valve check (pray for me on the valves, it'll be the first time for me) this weekend and seeing if that fixes it.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: scratch on March 14, 2007, 03:05:26 PM
This Saturday just opened up, so if you want to drive it down here Friday, I can do the valve adjustment this Sat.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: pandy on March 14, 2007, 03:11:55 PM
Are spectators allowed? (not for the valves...been there, done those...I just want to watch scratch work  :icon_lol: ;))  :kiss3: :icon_mrgreen:
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: brett on March 14, 2007, 03:20:52 PM
You know you have more than just first gear, right?  :laugh:

If the bike feels like it's running fine and you aren't noticing a big pool of gas on the ground after you park the bike, maybe something is up with the odometer? I find it hard to believe that a gs would only get 25 mpg without showing noticeable signs of defect. To check, you could either get someone to follow you (and compare odometers later) or ride an easily measurable distance.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: scratch on March 14, 2007, 03:30:13 PM
Quote from: pandy on March 14, 2007, 03:11:55 PM
Are spectators allowed? (not for the valves...been there, done those...I just want to watch scratch work  :icon_lol: ;))  :kiss3: :icon_mrgreen:
Sure!  I'll clean the barbeque, and ask the wife to get me some chicken, burgers, and/or turkeydogs.  Ceek can come too, if he's not being too anti-social.

Brett - how's your bike?  I only have one other person's bike to work on, and that's Snopyro's, and maybe Pharoh's.  I'll try to squeeze ya'all in before June.  Lot of family birthdays in April.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: RVertigo on March 14, 2007, 03:48:29 PM
Damnit!  I wanna come over....   :icon_confused:
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: Hawkster on March 14, 2007, 05:42:58 PM
Ping,

Your original post about your mileage got me to thinking...  The bike's fuel-mileage is a function of a number of things. 

If you don't have a fuel leak and the jetting is okay...

Rolling resistance can be a big factor.  How much pressure do you keep in the tires?  What shape are they in?  Is your chain in good condition and properly lubricated? Are the sprockets okay?   How good are your wheel bearings?  Are the front or rear brakes dragging?

Rider factors include rider-weight, smoothness on the throttle and not overloading the throttle.  (Only giving the motor as much gas as it needs to get you going.) 

If all those are fine, then I'd start looking at the motor.

Luck,

H~
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: pingpong on March 14, 2007, 09:07:02 PM
Quote from: brett on March 14, 2007, 03:20:52 PM
You know you have more than just first gear, right?  :laugh:

If the bike feels like it's running fine and you aren't noticing a big pool of gas on the ground after you park the bike, maybe something is up with the odometer? I find it hard to believe that a gs would only get 25 mpg without showing noticeable signs of defect. To check, you could either get someone to follow you (and compare odometers later) or ride an easily measurable distance.

I've actually thought about that too, and tested it out. Odometer seems fine, though (unfortunately).
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: pingpong on March 14, 2007, 09:53:14 PM
Quote from: scratch on March 14, 2007, 03:05:26 PM
This Saturday just opened up, so if you want to drive it down here Friday, I can do the valve adjustment this Sat.

What an offer.  :) Would definitely help me out a lot. If you're not busy already, of course. Would it be alright if I brought it down Friday night? I can probably get down by 7 or 8PM. And then come back sometime Saturday morning to work on it maybe?
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: scratch on March 15, 2007, 09:24:27 AM
Crap, crap, crap!!! Last minute family emercencies! I can't...again!  :mad:

How about Sunday?  Drop off Saturday eve?
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: brett on March 15, 2007, 12:39:31 PM
Quote from: scratch on March 14, 2007, 03:30:13 PM
Quote from: pandy on March 14, 2007, 03:11:55 PM
Are spectators allowed? (not for the valves...been there, done those...I just want to watch scratch work  :icon_lol: ;))  :kiss3: :icon_mrgreen:
Sure!  I'll clean the barbeque, and ask the wife to get me some chicken, burgers, and/or turkeydogs.  Ceek can come too, if he's not being too anti-social.

Brett - how's your bike?  I only have one other person's bike to work on, and that's Snopyro's, and maybe Pharoh's.  I'll try to squeeze ya'all in before June.  Lot of family birthdays in April.

Thanks for the offer, but she's mostly ok for now. I'm going to try and get a little wrenching in this weekend, but unfortunately my efforts on St Patty's Day will render me completely unfit to go near a bike on Saturday and probably hurting too much to work on one on Sunday.  :cheers:

I'm pretty busy for the next few weekends, but we definitely need to get a BAGS ride going sometime soon.
Title: Re: OK this MPG is just getting pretty ridiculous
Post by: pingpong on May 04, 2007, 05:16:42 PM
Sweet. I got the valves adjusted back up to spec (exhaust valve was around 0.2cm too loose!!! Running at around 45MPG now, much more improved.