The seals sit on the outside of the main bearings, for those who aren't understanding this whole deal. The seals hold the air/fuel mixture in the cavity, and the outside air or gear oil out of it. The seals on a Honda can actually be replaced via the outside and just press new seals in. Kawasakis and some others actually have the seals in the same place but a retaining metal tab that will not let you pull and repress new seals in, without taking cases apart. The sucky thing about Honda since they are so anti 2 stroke, is the fact that they did many things right, thus i've loved their bikes for so long. For instance, the CR250 and CR500 clutch cover was the same for both for many years. I used a CR250 boyesen basket cover for my 500. Things like that. Just making parts interchangeable for years, and making them last long, ease of changing etc. Just sucks they hate 2 strokes.