Can't speak to yambits, but if you have a local bearing company of any size near you, they will probably have many of the pattern seals your seeking. The seals have their size markings on the outside rim. Its a 3 digit sequence defining OD/ID and thickness. My experience has been that these seals are of high quality, but not moto-specific, so you're not paying for the OEM name brand. Plus, no shipping fees.
Good luck.
Steve