Motorcycle Repair: 4 Speed leaks from drive shaft, drive shaft, leaks

Question
QUESTION: This was supposedly rebuilt, at least the guy before me had receipts for it. I have replaced seals and after a few hundred mi. it starts leaking again. I am wondering about the bearings/race being worn. There doesn't seem to be much endplay on the shaft. Any info concerning common problems would be very much appreciated. Thank you for youe time and expertise.

ANSWER: Which seal is it leaking from?
Mike

---------- FOLLOW-UP ----------

QUESTION: It leaks from around both seals.Especially the mainshaft seal.  I am thinking worn parts.

Answer
Check the race that the seal rides against. It might have a burr on it or a flat spot rubbed on it and it might need replaced. On the other seal, check the mainshaft. You never said what year the 4 speed is from, but the early ones had a cork seal behind the race, so make sure its there
Good luck and happy riding
Mike