My homie in the old country got an early 60s BSA 500 single for 50 bucks. We were just teenagers but had some mechanical abilities already and plenty tools at our disposal. The previous owner had stripped it for dirt use and done a poor job at it. It needed lots of work. His first 5 minutes of working on it introduced us both to Whitworth. :wtf: is this? :lol: We were fully expecting metric on a foreign bike. Needless to say the Crescent wrenches got a lot of use :lol:. That thing had the biggest knobbie rear tire that either one of us had ever seen. You didn't dare get behind it in the rocks. Every time that big single fired it pitched baseball sized rocks :rofl: