Bill mentioned the countershaft O-rng. Take 2-3 of these as they will double for the clutch slave o-ring if it shits itself(2006 have hydraulic clutch). You can use baby oil, fork oil as the fluid in a pinch. DO NOT use DOT Brake fluid.
2006 also has a lock washer and large nut on the countershaft. In Australia I have always got a different type of lock washer than when I order in the USA. Using the Australian lock washer, you can bend the washer over the large nut (after fixing to correct torque and using loctite). This ensures the nut does not come undone. Take a couple of the lock washer as well.
I use Loctite on everything. If I don't use it, I lose the bolt/nut.
2005 KTM 640A
dnrobertson screwed with this post 12-23-2012 at 04:19 AM
Reason: Cannot spell loktight :-)