ok ill keep it short, is it 520x106. im guessing order the xr650l 13 tooth and not worry about the shop messing up the klx one. whats stock tooth size on the rear, i want to drop a tooth and juggle a 13 and 14 cs. i searched, but got way confused.

 

14/42 is stock. XR650L for the front. and cross ref anything for KX450F KX250F for the rear. JT sprockets do steel for both. Renthal have plenty of alloy options for the rear.
106 is stock and will allow you to juggle 13 and 14 fronts.