You can easily count them.
Front is 13t from factory on both R and X.
On the X the rear is 42t stock, and I think it's 43t stock for the R.
If you look at the rear you should have a stamp on it that tells you. Or count them.
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2008 WR250X
Gearing: 13t - 48t
Power Commander 5 / PC-V
Airbox Door Removed - Flapper glued - AIS removed
FmF Q4
Bridgestone Battlax BT-003rs