just get a 15t front sprocket. very simple mod, no special tools. new front sprocket is around $15.00

i just put on a 14 toother two days ago. very sweet.

see this post: new sprocket

http://www.gstwins.com/forum/viewtopic.php?t=14648

if this link doesnt work, the post should be on the first page, i posted it yesterday

So if I do a 15t about how many mph will i loose off the top end.  currently i get speeds of 105mph

i can actually get mine going faster now that i changed it b/c it pulls in sixth. before i had to be going down a big hill to get much over 100, but now i can on flat ground get 110mph. the rpm's were higher, but it will get there. i dont necessarily think that anyone "loses" top end, but that it just moves your torque curve down about 1k-2k rpm. it just accellerates quicker, and in my case, moved the torque curve down to where it could be used.

Do I need a different front or rear sprocket?  

 you would probably be better off changing the front. if you have a newer bike just change the front. go with a 15 or 14. i wouldnt change the rear unless you have to. If you change the rear, you would need a bigger chain too. if you go down in the front, you can use the same chain you have now.


What size?

go 14 or 15 i bought a jt sprockets front for like 14 or 15 dollars
if you do decide to change the back, going down one tooth in the front equals going up three in the back. but remember, if you change the back you need a new chain

Is it a hard procedure?

not to change the front. to change the rear, you have to pull the axle and drop the tire. to do the front, all you need to do is take off the bolts that hold the cover in place, remove the split ring, and change the sprocket. takes about 15-20 minutes.


Do I need any special tools?

no, to change just the front, all you need is an 8mm socket and a 10mm socket and a way to remove the split ring. i used a dull knife to pry one corner off, and then work it off of the shaft. same way to put back on.

what you need to do is loosen your chain all the way, loosen or remove your clutch cable at the handlebar, take the 5 8mm bolts out of the cover, it just slides off, then remove the split ring, and change the sprocket. i dont know your model year, but some of them have a shoulder on the sprocket. if you do, the shoulder needs to go on the inside towards the engine.

somewhere in the forum there should be a how to with some pics, but if you cant find it and have a way to get a fax, i can copy the pages in my clyimer on how to do this and fax them to you. just let me know john.paine@cox.com (email)

Here are a couple of posts with pictures to back up Johnboy's good info:

From the "ok i need chain, front and rear sprocket, where can i get?" thread

From the "Stupid question..but..." thread[/list:u]Good luck!

I didn't loosen the clutch cable, at least it didn't seem necessary to.  Just remove the sprocket cover and the clutch cable will stay attached to it.  There is a hot gold rear sprocket on Ebay right now which is a 45 tooth.  I think it's about a 1:3 ratio so it's just inbetween a 14t and 15t but closer to the 15t.  I think stock on the rear is 49t.

Dom
down on front or up on rear will get quicker acceleration

a 45T rear would be like a 17 on the front

Stock on the rear is 39 teeth.  A 45 in the rear would be like a 14 in the front, wouldn't it?

my bad....
i read Dom's post.....he said stock was 49....

bad thing with a bigger rear...longer chain=new chain

as stated earlier....

Hey thanks for the help sound like i will be doing this mod for sure.