I had Honda Foreman in the shop recently with an oil leak. The leak was at a faulty seal on the output shaft coming out of the front of the engine. The red arrow points to the spot where the lip of the seal is distorted.
To replace this seal the front drive shaft needs to be removed. The drive shaft has splines on each end and "floats" between the engine and front differential. The mounting bolts for the front differential are removed and this allows the diff to move forward about 2 inches. Once the differential is moved forward the drive shaft will slide right out.
Once the drive shaft is out of the way I used a pick to pry the old seal out. On small seals like this one it is normally easy to pry them out. Larger seals may be stuck tighter and require a little more work to get out. I have a couple of examples of this here and here.
Once the old seal is out it is a simple matter to clean the parts up and press the new seal in. A small seal like this can almost be pressed into place by hand. It only required a few light taps with a small hammer to seat it. When driving it in you must make sure that is not bent or distorted.