I'm currently conducting some research on the failures of the Tanio Koba Piston Cups to see if it could be caused by installation error, or failure in manufacture. The results may help me in claiming refunds for people if it's found that error is caused by manufacture.
I've sold 15 of these and 3 of the buyers have told me that they cracked it.
My main question at this moment is when installing the cup: did you install it so that it cups IN to the cylinder, or away from the cylinder. In other words, does it taper away from the cylinder or in to the cylinder, respectively?
Anybody who has had any Tanio Koba piston cup failures for their Marui Hi-Capa 5.1, please PM me with the answer to my above question.
Thanks for your help.