[Zeesaffa]

I've just bought an '07 250x.
The previous owner installed a 13 tooth front sprocket.

There is a really obvious chattering sound when doing any speed really but not necessarily when accelerating.
It also does it alsmost constantly when just cruising at about 5-6k rpm.

I'm not sure if it is the chain because of the smaller front sprocket or maybe the gearbox... or something else?
The slack on the chain is fine and is no more than my mates CRF and he doesn't get the noise.

Any pointers much appreciated!
Thx!

[dirtae]

If the sound is coming from the rear check your chain guide/block. Sometimes dirt/mud get in there and causes it to squeeze against the rear sprocket. Usually more of a clicking sound sound though. However, your chattering might sound like my clicking, lol anyway just something to check/rule out.

Put your bike up on the stand and rotate the rear wheel by hand and listen. If it is up front, pull the case saver off and look under it to see if it has any evidence of the chain rubbing against it, and inspect case/sprocket for anything abnormal. Also check the chain slider. Just trying to point out some of the more obvious stuff to rule out.

[mappsterr]

I am not sure what you are describing is what I was hearing, but I had a similar concern with my X.

See this thread --

http://www.crfsonly.com/forum/viewtopic ... highlight=


Hope it helps.