If the missed approach on the IAP says something like:

heading of 270 to 4000
Intercept the XXX VOR R-180
Direct to XXX VOR

What should you do if you get to R-180 before you get to 4000?

Keep climbing on 270 to 4000?

Turn and track the R-180 while climbing?

The IAP has no minimum climb gradient specified.

What minimum climb gradient is assumed if none is specified?