A collector must now be an expert on a subject that was of little consequence when the bike was built.

When it was manufactured, every motorcycle had at least one serial number. You, as a serious collector of motorcycles, must now be an expert on a subject that was of little consequence when the bike was built. First, mistakes do happen and bikes can rarely have genuine but wrong numbers through the process of factory or dealer replacement or legitimate restamping. The Vincent factory did in fact change a few serial numbers and number replacement cases either with new numbers or the original numbers. When it was manufactured, every motorcycle had at least one serial number. You, as a serious collector of motorcycles, must now be an expert on a subject that was of little consequence when the bike was built. First, mistakes do happen and bikes can rarely have genuine but wrong numbers through the process of factory or dealer replacement or legitimate restamping. The Vincent factory did in fact change a few serial numbers and number replacement cases either with new numbers or the original numbers.

Most importantly, remember that just because a bike has the correct numbers, they are not necessarily the original, matching numbers. Restamping is done in the car world just as it is in motorcycles. In some car marques, like Corvettes, it is common and accepted to have restamped engine blocks and proclaim "matching numbers." That's all it means - the numbers match today, but they didn't six months ago. In rare motorcycles, changing numbers is illegal and unacceptable. Having ORIGINAL MATCHING NUMBERS is a very big factor in the worth of the motorcycle. The Vincent Owners Club has issued Certificates of Authenticity on many motorcycles in the past, without having seen the actual numbers. They have relied on the word of the club member that these numbers are the ORIGINAL numbers. That is an assumption that can get one into trouble. Don't rely on a club certification alone on a very rare motorcycle. As to the numbers themselves, on Vincents, the engine number may have two or even three different sizes of stamped characters in the same serial number. Examine the plinth, or raised area on the left side engine case, for signs of tampering. Remember that on "C" Black Shadows, the plinth is generally removed while it still is there on "C" Rapides.