As some of you already know, I have a 1982 CX500 I rescued from Ebay and effectively rebuilt. (It's in other threads on the forum somewhere). The stator was replaced but then the water leak started (didn't leak before), so I've started the job of water seal replacement. I made a frame, clamped it to to a dolly so it met the underside of the engine and then removed the mounting bolts. Slid the engine off the drive shaft and then raised the bike leaving the engine free. Rear cover off - there's the new stator and the hole for the mechanical seal is the middle one at the bottom of the picture. This is what the engine has to come out for, inner oil seal and mechanical seal. Turns out that the aperture for some covers is 27.8mm whilst some are 28.3mm. You can only get seals which are 28.3mm. Guess which size mine is? Hello flap wheel and Aldi special buy micrometer! A bit of nervous "dremelling"followed. All back together for now. No way to know if it's worked until you put it all back together!