Only if the author has been acknowledged as an expert by reliable books newspapers and magazines Otherwise it doesn t meet Wikipedia s policy of Identifying reliable sources For example Kevin Ash is a journalist and published author and so his personal site on motorcycles is considered an acceptable source for some types of information I don t see what the problem is Why can t people just go to 1968k0 com instead of Wikipedia for this information I can think of many other similar personal web sites that focus on a single model of motorcycle which also don t meet Wikipedia s standards but that doesn t prevent people from getting the information