Motorcycle Repair: nighthawk 250 shaft seal, shaft seal, sproket

Question
hi, my 99 nighthawk 250 lost all of its oil this week when i tried to take it to class. it was a cold morning and i believe that may be a part of the problem.

the oil was leaking out out about even with the side stand and apon further inspection (without taking the foward sprocket off) it looks like the leak was coming from the seal behind the sproket. i have ordered the seal, but im now worried that im going to have to take the lower half of the engine apart inorder to replace a $5 seal to get me back on the road.... is this the case or can i simply press it on from the outside?

thanks
paul

PS, i did try to run it in natural (before i realized it lost ALL oil) to warm up the seal, and put fresh oil in it, but it ran out almost as fast as i could pour it in.  

Answer
Typically you can drill a couple of small holes in the side of the seal, put some self tapping scres in the seal and then use those to pull the old seal out.  Careful that you do not drill into the case.  I don't know if the nighthawk has a locating ring which may make things more difficult, but you can see that on the new seal.  Use a large socket to drive the new seal in and you should be good to go.

Good luck,  Jan