Try a SKF part number 99387. It's the right diameter (3 7/8") and covers an area on the shaft about 13/16" wide. Since the 216/235/261 cranks don't have a big rear flange for flywheel mounting, the sleeve will slip on. Secure it with RED Loctite. If you're using a rope seal, you might have lots of problems with the seal creating excessive drag on the crankshaft due to the increased diameter of the shaft with the sleeve on it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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