0
You really can't compare a v-twin and an inline twin in terms of weight.
The reduction in moving parts is significant, along with fasteners, plumbing, covers, etc. It's not by half for a inline vs v, but there isn't a second independent cylinder with all the extra support mechanics involved. Combining that with what appears to be a minimalist approach (read: not a GS-A), it should be quite easy to hit that weight.