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Main Area => General GS500 Discussion => Topic started by: murf425 on February 18, 2009, 08:33:05 AM

Title: 2 Questions...possibly dumb ones
Post by: murf425 on February 18, 2009, 08:33:05 AM
First of all, it's an '06 GS500F, it has about 11,500  miles on it, I'm not real up to speed on the mechanics of my bike yet.  And I will also preface these questions with awknowledging that it is currently behind on its maintenance schedule (I'll be remedying that as soon as I have time/money in a few weeks).

Anyway, my two questions:

I have it set to where it idles at 1,200 rpm, as per the instructions in the manual.  However, it seems to be revving unusually high lately at speed.  I'm not really sure what it used to be doing, but it is currently taching right at 5,000 rpm at 60 mph in 6th gear, and it goes up approximately 1,000 rpm for every 10 mph past that.  Is that normal?  6k at 70...7k at 80?  It also SEEMS like it's vibrating more at high speed recently than it was previously.  Not a hard shimmy or anything...just more/deeper buzzing through the tank.  Again...normal?

The other question is mileage.  When I first got it last summer, I was getting exactly 60 mpg out of it.  A few months later it droppsed to about 55...now on this last tank it was down to 48.  Granted, as my confidence has gone up I have ridden it a bit more aggressively, but I can't see where accelerating faster would cause THAT much of a drop.  Is there anything mechanically/maintenance-related that would cause such a severe drop off?
Title: Re: 2 Questions...possibly dumb ones
Post by: Paulcet on February 18, 2009, 09:22:25 AM
your RPM/speed ratios are good, unless you have a 17 or 18 tooth sprocket on the front.

Perhaps your 60mpg was on 100% gasoline and now you are using gas with 10% ethanol?  I have heard of up to 10% drop in fuel economy because of the ethanol.
Title: Re: 2 Questions...possibly dumb ones
Post by: Roadstergal on February 18, 2009, 11:25:20 AM
Throtle kills mileage, short trips kill mileage, rejetting kills mileage.  Underinflated tires don't help it any.
Title: Re: 2 Questions...possibly dumb ones
Post by: murf425 on February 18, 2009, 11:27:16 AM
Quote...unless you have a 17 or 18 tooth sprocket on the front.
Quote...rejetting kills mileage.
Everything's stock.  My typical riding is about 8 miles to and from work, 95% of which is 55 mph highway.

QuoteI have heard of up to 10% drop in fuel economy because of the ethanol.
I've been buying the same grade from the same station.  Maybe that whole thing with summer and winter blends being different?
Title: Re: 2 Questions...possibly dumb ones
Post by: Esteban on February 18, 2009, 12:26:41 PM
Quote from: murf425 on February 18, 2009, 11:27:16 AM
Everything's stock.  My typical riding is about 8 miles to and from work, 95% of which is 55 mph highway.

I've been buying the same grade from the same station.  Maybe that whole thing with summer and winter blends being different?
2 things:
1. My '07 with ~3700 miles on it has always gotten about 45-50 MPG when I ride solo (see my sig).  Riding two-up for me increase the fuel economy (because I'm much more defensive).
2. The station I purchase gas at recently put white stickers on their pumps that say "10% Ethanol", so you should check for those (here in NJ it's hard to tell when getting the car filled, but on my bike I immediately noticed the change).
Title: Re: 2 Questions...possibly dumb ones
Post by: Roadstergal on February 18, 2009, 02:57:14 PM
Quote from: murf425 on February 18, 2009, 11:27:16 AMMy typical riding is about 8 miles to and from work, 95% of which is 55 mph highway.

That's not a lot of distance to get the bike nicely warmed up...
Title: Re: 2 Questions...possibly dumb ones
Post by: natedawg120 on February 18, 2009, 03:11:02 PM
Quote from: Roadstergal on February 18, 2009, 02:57:14 PM
Quote from: murf425 on February 18, 2009, 11:27:16 AMMy typical riding is about 8 miles to and from work, 95% of which is 55 mph highway.

That's not a lot of distance to get the bike nicely warmed up...

that is correct, my commute to work is .. well .. walking distance at 2 miles, and when i would get lazy and not take the pretty 20 mile loop around the backside of Blacksburg home i would A) murder my battery, yay! and B) get about 38-40 mpg.  That was always a per week figure cause i fill up and ride on the weekends when I can, fill up for the week before Monday.  Its easier that way as the fuel guage on everything i own is the odometer, and who knows how long before that goes out in my truck everything else electric is :icon_lol:

PS: Bump starting gets old fast ... memories  :icon_lol: :icon_lol: :icon_lol: