My initial fitment of the Yamaha YM2C rear wheel in the Benelli swingarm showed me that some surgery was required. Specifically, I needed to employ the same technique I used on the The Bride’s Ninja 500 rear wheel back in 2001: cut off the part of the sprocket carrier that held the oil seal, and replace the carrier bearing with an “RS” sealed unit.
Unfortunately, this time around, the procedure proved to be a bit more difficult. No matter how I messed around with it, I could not get the casting chucked up in my lathe so that it was true and secure. (I could only get one or the other.) So, I resorted to lower tech methods. This modification doesn’t really require any precision except for appearance, so I held the sprocket carrier in the vice and went at it with the reciprocating saw.
Afterwards, I hit it with a sanding wheel in the angle grinder, then the detail sander, until it didn’t look obviously hacked up. I still might need to figure out how to chuck this chunk in the lathe, if I need to shift the sprocket. We’ll see.