I am new to this to an extent. I think they changed to a mono lever rear suspension and the side cover is different. Any other notable differences between an early 80's and late 80's R100? There is a 1981 R100RS that has caught my eye

http://www.ebay.com/itm/81-BMW-R100R...vip=true&rt=nc

as well as a 1989 R100RT

http://www.cycletrader.com/listing/1...0-RT-112833442

Any education is welcome. I understand the difference between an RS and an RT. Well, maybe not completely.