Alright first post..yay for me anyways okay this is my question and i hope someone can help out. i have a 1991 gs500e and i want to put a new rear sprocket on it. right now i believe it has the stock one which is a 39 tooth stainless steel. i want to put on a 47 tooth aluminium one. would i need a new chain to do this? or can i use the old one? and if you know what ind a chain i would need also thatd be great. thanks in advance for any help thats sent my way

Quote from: sukigirl85i have a 1991 gs500e and i want to put a new rear sprocket on it. right now i believe it has the stock one which is a 39 tooth stainless steel. i want to put on a 47 tooth aluminium one.

I'll just assume that you know what you're doing.  Can you say "Wheelie machine!"?

Quote from: sukigirl85would i need a new chain to do this?

Most definitely.  It seems to me that you would need to add one link per extra tooth, so a 118-link chain rather than the stock 110-link jobbie.

Quote from: sukigirl85if you know what ind a chain i would need also thatd be great.

You can probably order a length of chain with as many links as you want, but you might just want to buy a pre-packaged D.I.D. O-ring chain with the right number of links.

My 2004 printed Chaparral catalog shows a 118-link chain with part number 312-1918, but I can't get it to come up on their online catalog.  If nothing else you could order a 120-link chain (part #312-1920) and grind off whatever links you don't need.  The chain will come with a clip-style master link.  You can buy a rivet-style master link (part #312-1956) separately.

PS - Don't be afraid to shop around for other brands / prices.  You may get some useful ideas from my GS500 Chains & Sprockets page.

Welcome,

You will need a new, longer chain to wrap around your new larger sprocket. The D.I.D. brand has been suggested. You will also need to completely remove your chainguard, as I believe a 47 tooth rear sprocket will not fit under the stock chainguard.

Quote from: Kerry
I'll just assume that you know what you're doing.  Can you say "Wheelie machine!"?

that's my heather, so you know that's already what she was planning,



kerry, i'll look around your page, but do you know anywhere that sells just the clipstyle masterlinks spare links of chain, just something to make it convienent to switch back and forth between sprockets depending if we're in a parking lot, or on the highway? and does anyone have an estimated top speed of a -2+8 gs?

haha yea i have a pretty good idea that it will be a nice "wheelie machine" when its through. ive already modified the front sprocket and now im just looking for a wee bit more power you could say.. itll only be for recreational riding though

That's an interesting idea: you could have a 110-link chain, and some extra links (maybe 10?), then join them together using a C-clip masterlink, then join the chain on the bike using a second masterlink.  You could remove the extra links, leaving 110 for a stock rear cog.  Problems include: I believe  that it is not recommended to reuse the masterlink C-clip; and the 110 links would wear, even when the extra links aren't on the chain, which could produce some interesting stress on the cog.

I think you can order a masterlink separately for a buck or two, from wherever you order yourchain.  Some brands don't come with a masterlink, so you must order at least one anyways. (my DID came with masterlink)

Quote from: tt_fourkerry, i'll look around your page, but do you know anywhere that sells just the clipstyle masterlinks spare links of chain

I just updated the D.I.D. and Parts Unlimited sections of my  page -- but only the Chaparral and Dennis Kirk columns for now.

Don't forget that the D.I.D. boxed chains for sure come with  a clip-style link included.  But having some extras wouldn't be a bad idea....

So the old ratio was 16 front to 39 rear, or 2.4375 wheel revolutions per engine revolution.  The new would be 3.3571, an incrcease of 37.73%.  So if your old theoretical max speed at was 140 mph, the new would be (140 / 1.3773) = 101.65 mph, a decrease of 27.4% in speed for any given RPM.
Theoretical speeds at redline in each gear would be:

1st......35 mph @ redline
2nd......49
3rd......62.4
4th.......77
5th.......90
6th.......101.65

If you normally cruise on the highway at 5700 RPM, this would put you at close to 8k RPM... which is going to be touchy on the throttle.  With those sprockets, your 2nd gear would feel alot like 1st does now, and 6th gear would feel alot like 4th does now.  You'd basically be giving-up the current 5th and 6th gears, in order to get an extra gear down low.  So try riding around without using 5th or 6th gear and see if you can stand losing them.

Quote from: Kerry

Quote from: sukigirl85would i need a new chain to do this?

Most definitely.  It seems to me that you would need to add one link per extra tooth, so a 118-link chain rather than the stock 110-link jobbie.

118 is way too long
i have 114 links on my chain with a 48 tooth sprocket
and the stock front

one more thing with a chain that long if you have the center stand on the bike you will need to grind the inside of the left foot off some so the rivets on the chain don't catch on it


just buy a 120 link chain and a chain breaker and cut it to length yourself

Quote from: Rema1000So if your old theoretical max speed at was 140 mph, the new would be (140 / 1.3773) = 101.65 mph, a decrease of 27.4% in speed for any given RPM.

140 huh? my speed four tops out around 140, i'm not sure what her gs will get, i'd guess maybe 104, about 76mph top speed, that's plenty enough to make it to a parkinglot