its supposed to be like that. a shit move on yamahas part because they fill with water. I drill a small hole at the bottom as a drain. Some of the stuff that comes out is nasty!
The only thing i can think of is someone got carried away when they were matching the cases to the cylinder and it got too thin right there. on the outsides its possible to break through into either the stator or clutch cavity.
the ball joints are supposed to be automotive ball joints. i find the number off mine and get back to you. As far as the bushing go, mine use stock style bushings and dust caps.
trying to figure out where you figured that cpis were better than r2's
was there a dyno thread i missed?
It should be noted that rockets and r2's like alot of exhaust and transfer duration BUT seem to work well down to a dune port.