Here is a preview of the forthcoming MC16 & MC18 additions to the Online Parts Manual (and one reason for the lack of recent updates to the Site!).

MC16 Cylinder part numbers.

The 2 longer studs (part# 90031-KV3-000) are used on the lower head to secure the bottom radiator mount.

If your Honda dealer can't get you the original parts just try a good auto-parts store or jet-ski/waverunner dealer for something similar. The studs are a slightly awkward size as they are M7, but any M7 stud can always be cut to size.

Andy.
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