Honda CRF50F 2009 Owner's Manual page 107

Tire Replacement
The tires that came on your motorcycle were
designed to provide a good combination of
handling, braking, durability, and comfort
across a broad range of riding conditions.
Installing improper tires on your
motorcycle can affect handling and
stability. This can cause a crash in
which you can be seriously hurt or
killed.
Always use the size and type of tires
recommended in this owner's manual.
Front 2.50-10 33J
Rear 2.50-10 33J
Type bias-ply, tube
Use a replacement tire equivalent to the
original.
Replace the tube any time you replace a tire.
The old tube will probably be stretched and,
if installed in a new tire, could fail.
Have the wheel balanced after a new tire is
installed.
We recommend that tires be replaced by
your Honda dealer.
Servicing Your Honda
Tires & Tubes
99