I'm working on converting an Echo 58cc. I have often cut off the crank even with the rear bearing and plugged the block where the seal normally goes on my various Echo engines. The 24cc and below engines have cranks that aren't so hard, and it isn't very difficult to cut them off. But the 25cc and up cranks are HARD. It took me a while to cut off this 58cc crank.

Benefits:

Less seal drag.
One less potential leak point.
One ounce less weight. (I weighed it out.)
If you want to mount the crankcase flat to a firewall you have to cut part of the crank off anyway.

Is it worth it? Probably not....

Anyway, here's pics of this one. I have used modified car engine freeze plugs to block off where the seal would go before, but this time I "whittled" a plug out of Delrin plastic on the lathe.

AV8TOR