Relatively light (405lbs), built down to a price boxers that lack build quality of the earlier twins. Valvegear and pistons often need attention before 50,000 miles. Some jokers put R45 top ends on the R65! Also the LS model with shark-like looks but same engine. R45’s cheap (around £750), economical but very slow but R65 engine or top ends will fit. High milers may have transmission and even crank hassles.
‘79-84, 449/649cc flat twin, 28/50hp 90/110mph 70/50mpg