Originally Posted by Sirio2127

Mrx4-R03, is right you can not use any plus engine bearing in a jp apart from a jp modified Novarossi 35plus21 the jp-ro3 uses a 25.4mm outside dia 14mm inside dia and 6mm wide rear main bearing and the plus 21 rear bearing size is 26mm outside dia 14.5mm inside dia and 6mm wide. I wish people would do some looking befor they make recamedations. 1.6mm outside dis is a masive difrence and 0.5mm inside difrence is also huge. Regards Jeremy.