I have had a pair of these valves around but planned on using them with later forks which I have but not sure about going all in anymore to upgrade the 86 ITX, well I think I should at least put them in the 86 forks with proper springs already bought but I have so much abs goop holding my front fender together I dont want to disturb it. It has been repaired 3 times and finally has stopped cracking(bumpy roads up here). Anyway Main question is, do I drill holes in the damper rod with RPM fork valves, I think the instructions that came with the valves did not mention drilling.
No, you don't need to drill any holes.