Just a warning to others, i had trouble doing mine for the first time at midnight the night before a big ride. Anyway some 600km when cleaning the bike I noticed behind the sprocket a groove from my chain worn into my engine.

In a rush I managed to put the new spocket on with the flat edge facing towards the engine. It needs to have the spacer, stepped face going inwards if that makes sense. I have corrected now and does not seem to have done permanent damage to chain, sprocket or engine case. Although it did make wear marks on all three.

BTW with nuts like this I always give a coat of anti-seize now, stripped to many nuts through cold welding and soft alloy's.

And how come you guy's don't have the tools to get this off, it's the same size as the rear axle?

 

Ready for a change.

two 12s, 8 T handle, 22 on ratchet, 27 on impact and a hammer and chisel.

Pepsi and some tunes, optional.

 

Changing the front sprocket was as easy as....well changing the front sprocket. LOL I had my wife sit on the bike with it in gear with the rear brake pushed down and used a 1/2 inch socket and a small cheater pipe, it came off no problem. I would say its one of the easiest things to do on the bike. And just so you monkey's don't ask how big my wife is sitting on the bike, I have included a couple of pictures. hahahahahaha

 

what is the 8 T handle for?

 

the case saver?

 

Yep

 

just completed this project like an hour ago...14T to a 15T front sprocket....slightly jack up the bike...just enough to lift the wheel barely off the ground....

removed the sprocket cover (two top/left bolts)....flatten the washer...27mm socket on a impact wrench (could not get the bolt to budge with a breaker bar) $40 from harbor freight...should come off like butter...

rear wheel..27mm left bolt...right bolt..use needle nose pliers to bend the pin straight and pull out....22mm to loosen the right bolt....12mm open wrench to loose the small bolt away from the wheel bolt first...loosen that all the way to the head of the bolt....do the same on the other side....tighten the bolt head near the wheel bolt all the way in....push the rear wheel all the way in....

might be good idea to remove the two screw on the flat long chain protection on top...move the plastic strip over to the rear coil...getting the sprocket off the chain was a bit of a challenge....pull and try to push up...slowly spin the rear wheel clockwise why pulling and pushing the sprocket up...kind of work it up behind the frame and you'll be able to take it out once it's near the chain protection strip....it was a bigger challenge getting the bigger one in....i place the sprocket near the chain protection strip and on the chain....slowly turn the rear wheel counterclockwise...work it forward....once you are near where it belongs...pull and work is down while spinning the rear counterclockwise...it'll be tight, but it slipped in and slid it on...washer back....bent the end...with the larger front sprocket i was not able to put the metal piece on the cover....i just placed some washer and put the cover without the metal piece...

with the rear wheel..i found that setting the rear wheel with little more slack on the chain is better....use the 12mm bolt to push out the wheel micro-mm at a time and going from left and right side...continue to test the slack of the chain....check to make sure the wheel is straight...once you are good...tighten the second bolt away from the main bolt....make sure the wheel bolts on left and right is on tight....spin the wheel and listen for any grinding...should turn with ease....

just did an hour long 50 mile ride...now..i'm at roughly 76 rpm at 80 mph...before with the stock 14T...i was about 81 rpm at 80 mph....use this bike for commuting in san francisco city and freeway trips....this feels perfect now for me...the bike has a little less "jump," but it's a perfect san francisco city bike now....

it took me 1.5 hr exact...i was scratching my head on removing the sprocket off and off the chain for like 20 minutes...i wasted about 25 minutes because i kept having too little slack on the chain....so had to redo and push the rear wheel over and over again...it's best to just give yourself lot of slack from the start..and tighten the little bolts to fine tune the slack....next time..i think i can do it in less than 45 minutes....

 

ahnh666, next time you change the sprocket try it with the with the chain off the the back sprocket.

 

i had a stock a 2009 klx250sf front and rear sprocket...even with the rear wheel pushed all the way in...i did not have enough slack in the chain and could not get the chain off the sprocket...hence the 20 minutes of scratching my head...

 

BUMP,,,,
for Jhoffy to read.