Well i got a question for you guys.   My awesome bike.. when i start out fast and go through the gears.. as i reach speed of 80-90 mph  i am at i think 4th gear.. at this point i have throttle revved all the way trying to get faster.. this is when i experience something weird.. it seems the motorcycle actually slows down... like its running out of gas or something..  as i get to 100 it pretty much doesnt matter if i have the throttle turned all the way..it just wont go any faster and i have the sensation that the bike is slowing down.. as i go back to to say 70-80  i can feel that power of the bike again kinda pulling me...   but as i get to higher speed. it seems to get there then slow down intermitently like running out of gas or something.

I know its not out of gas as i just filled it.   Is this normal?  i have a gs500f 08.  Any thing i can do to stop this from happening?

I dont speed often..just a ramp that i get on its really long.. and is basically a tunnel like.. so i have fun in that area then once past it go back to speed limit...   but kinda sucks that it wont go any faster than 100mph..  its good i guess but i just wanted to ask the question here.

The GS just doesn't have the torque at high speeds to overcome all the wind resistance and friction against it. Most GS's depending on modification top out at around 105-115 indicated which in reality is right around 100mph. If you want to go faster you need a different bike, even if you throw another $1000 at the bike you may only gain a few mph.

yup

Quote from: Bluehaze on January 26, 2009, 11:44:07 PM
Well i got a question for you guys.   My awesome bike.. when i start out fast and go through the gears.. as i reach speed of 80-90 mph  i am at i think 4th gear.. at this point i have throttle revved all the way trying to get faster.. this is when i experience something weird.. it seems the motorcycle actually slows down... like its running out of gas or something..  as i get to 100 it pretty much doesnt matter if i have the throttle turned all the way..it just wont go any faster and i have the sensation that the bike is slowing down.. as i go back to to say 70-80  i can feel that power of the bike again kinda pulling me...   but as i get to higher speed. it seems to get there then slow down intermitently like running out of gas or something.

I know its not out of gas as i just filled it.   Is this normal?  i have a gs500f 08.  Any thing i can do to stop this from happening?

I dont speed often..just a ramp that i get on its really long.. and is basically a tunnel like.. so i have fun in that area then once past it go back to speed limit...   but kinda sucks that it wont go any faster than 100mph..  its good i guess but i just wanted to ask the question here.

100 mph in 4th? Are you sure you aren't flirting with the redline? I'd shift up to 6th if I was trying to get max speed out of the bike. Also, there is a decent chance you are suffering from the same vacuum operated petcock problems every other GS seems to have. If you are revving really high for a long time, it is quite possible that you're running into petcock issues.... You could try making your next run on prime to see if it was any better... Also, it is a GS, if you want to go 200 mph, go get a Hayabusa or something. The GS is plenty fast enough to exceed any limit you're likely to run into, but it isn't exactly a street legal racer replica.

You won't reach max speeds in sixth. Generally I find max speeds on my bike to be in fifth. With a good tuck on my GS500F I have seen 130 indicated. In reality that translate to about 117 mph real. And yes the increase in power from 3/4 throttle to full throttle at high speeds feels negligible. I think you probably need a more powerful bike if you need to be going that fast.

just a thought at 100 + you can bet when the cop does catch you you will be getting in the back of his car and your bike will be going for a ride on the back of a tow truck.  On any roads other then montana at 100+ your also 30+  the speed limit so your looking at a huge ticket and alot of points on your lic as well.  just a thought

A GS500 would redline at approx 106 mph in 4th gear but the power peak is at approx 8500 rpm or approx 8500/11000x106= 82 mph.  That's the point you feel like your slowing down in 4th as your power drops off.

In 5th gear power peak is at 124x8500/11000= 96 mph approx.

In 6th gear power peak is at 140x8500/11000= 108 mph approx which is about the tested top speed of the GS500.



If you do a good job of modifying the exhaust, intake, and jetting you can push the power curve up and go straight to jail without passing go.   

Annies dyno runs on modified bike:

http://img.photobucket.com/albums/v443/jcp8832/AnniesGS500dynoRun.jpg

Standard dyno runs without mods look like this:

http://img.photobucket.com/albums/v443/jcp8832/MikesGS500dynoRuns.jpg

+1 What Jack says.   

+1 to everyone.

Thank all for the response.. i dont really plan to go any faster nor keep that speed up.. i just thought at that point that my bike may be having some type of mechanical issue.    I love my GS and glad it CANT go any faster.. i just wanted to make sure it was meant to be and not something i may be doing wrong or a part doing wrong.   Very well written response.. THank you thank you thankyou.