GStwin.com GS500 Message Forum

Main Area => General GS500 Discussion => Topic started by: GoateeChicken on July 08, 2009, 08:24:43 AM

Title: A Few Questions - Sprockets, Speedometer
Post by: GoateeChicken on July 08, 2009, 08:24:43 AM
Eh boys,

1.)
Im new to the forum, and was just looking to get a few answers before I switch down to a 14 tooth sprocket on my gs500f.
Im running a 520 chain with 120 links, and was wondering if I went down to the 14 tooth in the front, I would have to buy a new chain?
The chain has 13k on it. Could I just take out a few links to manage for the less teeth?  :dunno_white:

2.)
Will a change in the front affect the gs's speedometer? I've heard from some that it will, and some that it won't. I was wondering if you guys knew for sure if the gs
runs off the front wheel for the speed indicator or off the cams. ?  :icon_question:

3.)
Also, just wondering if anyone has done this upgrade and how much comfort you lose at highwayspeeds.
Seeing that the rpm's will rise around 1000rpm.

Thanks!  :thumb:
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: 08GSSteve on July 08, 2009, 10:23:59 AM
1.  no you do not need a new chain + / - 1 tooth is ok
2.  no a sprocket change will not affect your speedo as the speedo drive is connected to the front wheel and not the gear box.
3.  about 500 to 750 rpm and not much speed difference (about 10km/hr)

:thumb:
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: bassmechanicsz on July 08, 2009, 10:53:07 AM
you can use the stock chain while using a 14t sprocket up front but you will just have less adjustment with the chain.  Depending on how much you have already adjusted it you might need a new chain.
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: VSG on July 08, 2009, 11:46:43 AM
Just a couple of things:

The stock chain length is 110 links isn't it?

The stock front sprocket is 16t.

So you'd be going down 2 teeth in the front and you already have a longer chain.  You'd need a 110 link chain, maybe smaller.

I thought I read somewhere that you need to remove a couple of links off the stock 110-link chain for a 14t sprocket.  Or it might just be what bassmechanicsz said.
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: tt_four on July 08, 2009, 01:15:28 PM
You may have to remove a link, but one link of chain covers 2 teeth on a cog, so you shouldn't have to do more than that. It's not too hard to shorten a chain.

Highway speeds? I went a little crazy on mine, and now my bike tops out at 95mph, so I don't do much highway riding anymore. A 14t cog shouldn't give you any trouble.
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: gsJack on July 08, 2009, 01:27:53 PM
Sprocket center distances:

http://gstwins.com/gsboard/index.php?topic=44849.msg502495#msg502495

Some speeds in gear changes for 14/39T tooth sprockets compared to stock 16/39T:

http://img.photobucket.com/albums/v443/jcp8832/GS500gearing-sprocket-rpms.jpg

Put your stock geared bike in 5th gear on the freeway and that's what you'll get in 6th gear with 14/39T.  I used to run freeways in 5th gear when running with big twin friends to match their roll-ons, it's hardly noticeable when your having fun.  Who hasn't inadvertantly left their bike in 5th gear on the highway and not even noticed it for a while?
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: 08GSSteve on July 08, 2009, 11:28:37 PM
oops me bad thanks for the correction VSG.  me thinking 15t stock

1 front and 3 rear will do same job but an extra sprocket change
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: rohde88 on July 09, 2009, 09:00:02 AM
Quote from: GoateeChicken on July 08, 2009, 08:24:43 AM

3.)
Also, just wondering if anyone has done this upgrade and how much comfort you lose at highwayspeeds.
Seeing that the rpm's will rise around 1000rpm.

Thanks!  :thumb:

not sure what you consider highway speeds, best to put an actual number range.

I went down to 15 and it's kind of annoying from 75-85 where i cruise at. The bike vibrates and can make my throttle hand numb after 30-60 min.

And I definitely notice if I leave it in 5th on the highway, I usually find myself shifting to 7th all the time, only to find that at 40mph I'm already in 6th :(
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: bassmechanicsz on July 09, 2009, 09:07:45 AM
I run a 15/40 and have no problems with vibrations at highway speeds but then again i usually top out at 75mph since i usually avoid highways as much as possible.  Only once have i actually gone a 65mph speed limit road and that was only cause i was lost in Trenton for a half hour and couldn't figure out how to get out.  Was a nice ride until i got lost and couldn't turn around even illegally.
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: Bluehaze on July 09, 2009, 10:43:17 AM
I have been running a 14t sprocket for a couple of months now. I have an 08 gs500 exactly 1 yr old.

1. no need for  a new chain because it was new..   i did have to use up most of my slack adjustment area.. its close to as far as it can go.

3. hwy riding is fine.  at 80mph  its between 6.5 to 7rpm  at 90mph its at 8-8.5rpm.  Dont notice the vibration at all.   Its a lot of fun with 14t as you dont need to downshift to pass.
on average  my rpm when on hwy stays between 6.5 and 8.5.
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: JB848 on July 09, 2009, 11:36:38 AM
Now I don't feel so bad knowing I am not the only one that shifts into 7th gear on a regular basis  :technical:
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: GoateeChicken on July 13, 2009, 02:06:51 PM
Alright guys, thanks for all the info!
So what I got out of that is,
Shifting to 14 tooth - Switch down to a 110 chain - Speedometer won't be changed.
THANKS!
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: Cal Price on July 13, 2009, 03:06:25 PM
I just replaced chain and sprockets and on the kit it says that going to a different size can affect your speedo.
Title: Re: A Few Questions - Sprockets, Speedometer
Post by: GoateeChicken on July 13, 2009, 03:53:53 PM
Quote from: Cal Price on July 13, 2009, 03:06:25 PM
I just replaced chain and sprockets and on the kit it says that going to a different size can affect your speedo.

It cannnnnnnnnnnnnnnnnnnnn, but on the GS500, if you look at your front wheel, there is a black cord going down to the left side of the wheel and is directly hooked up to the speedometer, meaning that the speedo runs directly off the front wheel's rotation. So, changing sprockets will not affect the speedo. This is only the case , usually on larger bikes where the speedo runs directly off of the driveshaft.

Its alllllllllllll gooodddddd....

:thumb: