Cylinder to crankcase matching

[NYSingh]

The YouTube algo took me down a rabbit hole of modifying crankcases to match the cylinders (ex https://www.youtube.com/watch?v=5nFcgDMzlZE).  Searched the forum and facebook groups and didn't really see much discussion on this for RDs.  Is there any benefit/need to doing this on RDs, or is it more of a small displacement thing?

[1976RD400C]

I don't think there is any need to worry about that on an RD, they match up pretty close. You could take the new gasket and position it on the cylinder, and then the case, to check it is not hanging into the port area and obstructing.

[85RZwade]

I think it was in Bell's book that I read something to the effect of "no tuner can resist doing it, but the benefits are negligible". I can't resist doing it!

[m in sc]

unless there's a big step i never bother.

[NYSingh]

I traced out the profile of the cylinder bases and compared them to the case and they lined up pretty much exactly.  Well done Yamaha engineers of 50 years ago