have a look at any wheels designed for the mid 80s tz Yamaha's pretty sure the n, s and possibly t models had these sizes as standard . the original yamaha wheels where a 3 spoke design and quite light . in the uk the rules mean that very few of these are raced [ if any , they where not a great bike ] so perhaps you could find a set . bill howarth has imported quite a few of these from japan over the years , most go to collectors who have no need for spare wheels , its possible he may have a set . i would think a set would be worth about £400 , is this in your price range , or do i have to rack my brains again!