Now I just have to find a way to buy it in Australia. 

Quote from: galahs on November 21, 2009, 05:58:58 AM

Do you know what brand sprocket it was?

We moved house since then, but I just found the packet it came in..."Jomthai Asahi Co Ltd" It claims to be Japanese steel, but made in Thailand. Has done 18,000km now, no problem. I like the gearing better with the 17.
Local bike shop ordered it in, took a few days to arrive and cost $24.50.

I noticed you can get Sunstar 33317 sprockets on http://www.amazon.com and http://www.powersportsuperstore.com and they ship worldwide for a reasonable sum.



I did a search for JTF51217 at www.powersportsuperstore.com and I noticed that the product that came up was for a 1994 - 2006 Yamaha YZF-600

Yamaha YZF600R-W <<<<< 520 Chain Conversion



Suzuki GS500 F-K4,K5,K6,K7,K8,K9




Seems the sprockets are interchangeable  

Wow!

I am really enjoying this 17 tooth mod.
It has made high speed highway riding so much easier.

The bike doesn't feel like it is being over worked anymore at 100km/h . And the taller gearing hasn't really effected low down acceleration much at all. If anything it makes 1st gear more usable as you don't have to change out of it quite so quickly.

The bike feels much more relaxed, I wish I had this mod when I did my 12,000km 3 week trip.

I would definitely recommend this mod for anyone who does more highway than city driving. Over 80km/h (50mph) it really shines.

I'm glad you like it. I am on the other side though, I went down to 15 and love it.
But I do mostly city riding. Each to his own, right? 

I have 15t and love it for all-around riding, if I did less freeways I would definitely get 14t though. BUT if I was going on along trip all freeway I would for sure go with 17t. honestly I dont think the 16t was good for any thing, it seemed to always be in the wrong gear.

It seems sprocket changes are one of those mods that actually make a noticable change to the bike.

I probably rate it 3rd of my list of mods now. 1. Front Springs, 2. Upgraded Headlight globe, 3. sprocket

Like I said I do alot of highway riding and this new sprocket makes me keep looking at the tacho and smiling when I notice it never goes above 6,000rpm anymore 

Can you make this mod from 15 to 17 and keep the original chain or should you do all together??
I do the Woodford to Minto trek every day and have considered the change but was warned off with 'to hard in 1st' comments, good to hear the opposite from some one who has used it.
Old man

Yes, you can use 17T front sprocket with a standard 110 link chain, only moves axle forward .148"

http://gstwins.com/gsboard/index.php?topic=44849.0

For those who've done this mod. Correct me here please...

With a 17th I need less revs for the same speed. This is a given.

At highway speeds - 5th and 6th gear - 6th is pretty well totally gutless at anything under 4.5k - which in Aust is 90kph or 56mph. At 100 to 110 kph (5 to 5.5k) sixth is fine. 120 and the bike sits around 6k.

How much lower are the rpms then? Are now forced to ride in 3rd (say 60kph / 38mph) whereas it was doable in 4th before?

For instance, regardless of the speed, riding in 4th at 3k is somewhat lugging on the engine. So you ride in 3rd instead, right? So is that what's happening with this mod? A tendency to now ride one gear down because of engine lugging if you rode at the old speeds in the old gearing?

Trying to get a feel / idea of how the bike powers with the mod.

Michael

100 kph = 62.5 mph.  Stock geared GS with std size tires turns about 4730 rpm at 60 mph.  With a 17T front the engine would turn 16/17x4730=4452 mph.  Not a real big change.

Same completely stock GS in 5th gear would be turning .961/.851x4730=5341 rpm at 60 mph or 16/17x5341= 5026 rpm with a 17T front in 5th at 60 mph.  I used to run my 97 GS with a 15T front in 5th gear on the freeways when running with big twin friends to match their roll-ons, 16/15x5341=5697 rpm at 60 mph.  Pulled nice.

You can figure the rest:

On our first trip to the Smoky Mtns in 2001 I had a MT90-17 K491 rear touring tire on my 97 GS so 24.1(dia oem Excedra)/26.18(dia K491)x4730=4354 rpm at 60 mph.  Less than the 4452 rpm above of a 17T front with std tires and it wasn't bad, recall I only downshifted to 5th a few times on the freeways for upgrades. And we didn't go 60 mph on the freeways, that's just a common reference point.  Nice economy rpm I think, we still have the 6 speeds when needed.

Thx gsJack. 

Yep. I can figure the rest.

Michael

Just happened to think my 02 GS has a 150/70 Roadrider on it now that has a 25.8" diameter so it's just about the same as a standard tired GS is with a 17T front.  My 24.1/25.8x4730=4418 rpm compared to the 17T with standard tires that was 4452 above at 60 mph.  No big deal but I do get a solid 60 mpg all around summers on my 02 with no noticeable loss of fun.

Michael, basically you are about one gear lower than before most of the time. I never use 6th now around town, so there are fewer changes to do which is nice, but I have an 'overdrive' for the highway. I've never tried a full comparison, but I'd guess the top speed would be higher in 5th than 6th on my bike with me and a top box on it. I just like the more relaxed touring revs.