Do R5/RD cases have to be used as a set?

[pdxjim]

LC and I believe RZ cases have a number hand engraved at the case exterior at the left side behind The stator.  Dunno if this is the same with AC cylinders.

The top and bottom case are engraved with the same number.

[85RZwade]

In my barn, all the RZ cases and the LC cases have the hand-engraved numbers, but my '75 RD cases do not.
Wade

[m in sc]

agreed, the liquid cooled cases do, maybe the later european aircooled's do, but not the 1st get aircooled's.

[sav0r (CL MotoTech)]

My rd350 cases don't match. It seems fine.

[Jspooner]

When I mocked up the motor and frame in my TZ replica I use an AC lower case and an LC upper case half. They bolted right together. There are some things that are not even close because of design but the things that are the same location like the crank, the counter shaft and I think the input shaft all matched like they were machined together. With that being said I would say they hold pretty close tolerances and would not be afraid to mix up upper and lower case halves of the same generation of engine.