I bought a Moose Racing gasket kit to rebuild my WR400 and am not pleased in the least with it. It was missing virtually all of the o-rings. I had to go to Harbor Freight and buy a metric o-ring kit (which by-the-bye worked very well). It came with some extra parts that who knows what they're for and was missing a few other parts it should have had. I contacted my supplier, a local indy, and he contacted his supplier (Parts Unlimited) and they basically said oh well. I make do, put it together and the stator cover gasket starts leaking right away. So, okay, I order a factory gasket and make do AGAIN. Then I run it in very carefully. No other problems noted, so yesterday I take it out on a long ride. And, guess what? Yup, the valve cover gasket starts leaking like a sieve. Word of warning.