A: When it's from China or elsewhere in the East. BEWARE. There is a Canadian seller right now trying to pass off a knockoff bike (probably a Chang Jiang) as a valuable immaculately restored wartime bike. It is certainly not one, and I've seen this tried before. The Chinese have been offering 750cc machines, usually with sidecars, in side- and overhead-valve twin models, for decades. They've been available in military paint to make the cheese more binding. The current listing doesn't even give an 'R' number, 'cause there isn't one. Fortunately the Chinese were always sloppy (or maybe conscienscious?) enough to use bad serial numbers. These can be looked up on any of a number of informative websites about BMW bikes, and the pictures for particular models can be compared to bikes being offered for sale. The Russian 'BMW's, i.e. Urals and Dneprs, are usually sold that way, and with their own model numbers which superficially resemble Beemer numbers, e.g. 'M-72' instead of an R-71. But the Chinese bikes are just a cheap mass-produced product, with no thought to such niceties as model numbers. Not really. So they are easy to slap shiny new BMW roundels on, and try to pass them off as legit Beemers. The current bogosity even has a roundel stuck to the front of the engine block, which to my knowlege BMW never did. I know it's hard to believe any seller could be so sleazy, but I've seen it with mine own eyes. And even with real Beemers, 'restored condition' means pretty much anything the seller wants it to mean. But that's another Guide. -woodwakr