R80:‘79-80, 797cc flat twin,50hp 110mph 50mpg 410lb R90:‘74-77, 898cc flat twin,60/67hp 120/130mph 55/45mpg R100:‘77-84, 980cc flat twin,60/70hp 115/120mph 55/45mpg Classic twin shock Boxers age well. Later models have better transmission but poorer economy. R75/80’s the best model, especially with RS fairing, but the good ones are very rare – owners don’t want to sell. R90/100’s have weird handling and excess vibes, engines go after 50,000 miles (smaller bikes can do twice that). Clutch, timing chain, generator and valvegear likely problems.