Got some interesting info on these shocks.
Page 14-25 rfy are rip off of ohlins 36 shocks but that lack the bleeder hole. Milled and drilled and taped mine for the screw
I asked if I should drill and tap the top boss or the bottom.
Either is fine. I installed a screw with a hole through it so a could attach a hose with the boss up and get all the air out of the oil side and set the level in the reservoir
Then he sent me this
I've got the same shocks on my KZ750LTD. Really happy with them, they've been on for a few years now and held up well.
From what I've seen (and what everyone else as told me), the main issue with them is quality control, but not in the machining so much as the assembly. Without the bleeder getting them assembled without letting air into the oil is difficult, so while some are good out of the box, some are not. You can take the spring off without a compressor and try compressing the shock - if the travel is smooth all the way along, congratulations you've won the QC lottery! But sometimes there will be extra air in the line and it won't move smoothly. The only way to fix this is to tap in the bleed nipple as mentioned above, or dismantle and carefully reassemble without letting air in.