Patrick,
Did you check the breather cover and what is inside????
The breather cover is to the left just behind the carb.
If the weep hole is stopped up inside the cover, it will leak!!!
If you are 100% sure it is not coming from the breather cover, then check elsewhere.
The cam cover with dipstick hole could also be cracked or broke.
ALWAYS check the easiest to fix places first, then check the hard to fix places last.
If in deed it is the crankshaft seal on eiter end, you would not have to tear the motor down, just remove the old seal and put a new one in.
When trying to determine where the leak is, clean the suspected area real good. Then run the motor a little and see if it is coming out of the area again.
Hope this will help.