Hi, I'm planning on buying a BMW from the 50s, and would like to know if there's something I should be aware of? Ie. parts that I should pay special attention to? My eyes were originally set on a R25/3, but it's only 250ccm and since my own weight is about 110kg it perhaps should go for R51/3 instead? I kinda like "the look" of the R51/3 over an R50, but the R50 is newer and perhaps recommendable due to the updates it got? The R6x are outside my budget, except if there's really good reasons for buying one of those instead.