Plain nuts come in different heights standard or flat, different pitches standard (coarse) or fine, one bevel or two sided bevel, and standard or small head. Sorry but you will have to choose from that many options and of course the material and platting!
Japanese motorcycles usually use one bevel nuts with fine pitches for M10 and above. So you may need M10 x 1.25 and M12 x 1.25 which are not common in hardware stores and overpriced in bike shops.