LC50 has some very minor differences from the MJ50
1) LC50 dampener plate is flat on the outside, MJ50 is not.
disassemble your LC50 Transmission (same steps as MJ50) to replace the crank seal
Remove the exhaust. remove the transmission cover. Note the bolts are different lengths and the oil drain bolt must also be removed.
To the left shaft. Insert your circlip pliers into the circlip and hold with one hand, with the other hand pull on the gear behind the clip and then sqeeze the pliers. note the location of the notched washer.
You just removed this gear, on the backside is the ratcheting hoorah, works exactly the same way as the ones inside a bicycle cassette; allows the rear wheel to spin forward without engaging the crankshaft.
theres a wierd washer thinger and a bracket to remove, now you can yank out the seal. The seal's inner radius is actually a bushing you'll need to slide out. put the new seal on the bushing before sliding it back into place.
now go backwards to reassemble.