Now, here's a question. I decided to change pads and seal on the brakes on my modern bike, which was a learning experience after years of drums. Anyway, my 2005 YZ125 has a twin piston front brake and single rear. The front pistons have small plastic inserts in them and the plastic is what bears on the brake pad. The rear though does not, it's just the plain metal piston with no insert. My son's ZX2R has inserts in all pistons. The YZ125 parts fiche and workshop manual show pistons with no inserts. What the? Should I have an insert in my rear caliper piston? Does it matter?