I'm installing my new 15T sproket but this one doesn't have the "shoulder" piece that the clymer manual refers to (and that my rusty old OEM 16T sproket does have ('91)).... I remember seeing someones webpage which described what to do for this, but I cannot find it now. The sproket w/o shoulder has some play it.  Can somebody please let me know if i can just use a big washer or something, or did I order the wrong 15T sproket?? Thank you.

I think i found what I was referring to:

http://www.gstwins.com/forum/viewtopic.php?t=2244

but seems a bit unclear... Kerry and GSjack, I guess I don't need the spacer if my rear wheel is aligned properly? or is the washer fab a must (or other sproket, but would hate to wait for shipping....)

thanks again guys

You shouldn't need to fab anything if you're just swapping to a 15t sprocket. Slide it on the countershaft and install the snap ring to hold it. That's it. If you lost or broke the snap ring, go to the hardware store and drop $4 on a box of 'em.

ok, but the problem is that the two sprokets are not exactly the same width since one has a shoulder and the other doesn't.... the clip is good. it holds the sproket in place, but it does have some play in it... ie, i can wiggle it around.....

I think what he is refering to is that the OEM and some AM sprockets have about a shoulder around the center that makes the splines about twice as thick as the sprocket teeth.

I wouldn't worry about it. Most of my different counter sprockets are the flat "thin" type and I haven't ever had any problems.  The chain holds the sprocket in the right place and both the shaft and sprocket are hardened steel.

thanks guys. I installed it as is, and it seems fine..... so we'll see how it holds up and if any problems I'll let everyone know... but I think its nothing to be concerned with... thanks for the help.

FYI, I have a 96 GS which apparently has the spacer/shoulder for the 16T stock front (countershaft) sprocket. If you go to www.bikebandit.com you can order the 15T front sprocket from SunStar (mine was part# 33315)  specifically for your model and year like I did:

Years 89-93 - Sunstar front (countershaft) sprockets are $13 + $6 S&H
Years 94-99 - Sunstar front (countershaft) sprockets are $21 + $6 S&H

step 1) SELECT Performance/Replacement Parts
step 2) SELECT Chains & Sprockets
step 3) SELECT Sprockets/JT - SUZUKI
step 4) SELECT SUZUKI GS-500E (89-93) or SUZUKI GS-500E (94-99)
step 5) LOCATE "Sunstar Counter Shaft Sprockets" and CLICK ON DETAILS
step 6) CHOOSE number of teeth you want (14, 15, 16) and ADD TO SHOPPING CART

I know some people say the space/shoulder is not necessary, but I would not want to take any chances. BTW, the aftermarket spacer/shoulder is alot beefier than stock. Click on http://www.gstwins.com/forum/viewtopic.php?t=2244 and scroll down if you want to see Kerry's comparison pics: