Kit pistons are numbered 1,2 and 3, all 4 hole. I assumed they were corresponding to 1.1mm, 1.2mm and 1.3mm holes, but I just looked at mine and its not the case.
Piston no.1 seems to have 1.4mm holes
Piston no.3 seems to have 1.2mm holes
Piston no.2 is in my front shocks at the moment, so I can't check. I'd guess 1.3mm?
I've used the shafts of my 1.0->1.6mm drills to check, along with my vernier callipers to check the drill bit shaft.
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