matching numbers?

what does this mean exactly? I am completely new to motor cycle restoration. I have read alot about matching numbers. Frame and engine numbers? does this mean that the numbers actually are the same or in a series? I have a Norton ES2 1953 it is all a part and looking at the numbers I can find on the frame. I have several different numbers on the frame. Like I said before I am totally new to the Norton world and have many many Questions.
Thanks in advance for any info. I suppose pictures would help a bit.... I have looked in the spots recommended as far as where to find the serial numbers but am just a bit confused as to what means what.

COMPLETELY matching numbers is when the serial number listed on the title matches both the frame and engine serial numbers.

Norton engne serial numbers are stamped on the left side of the crankcase, just below the cylinders.

Frame numbers are stamped on an I.D. tag, riveted to the headstock, up until the last models that had a frame serial number stamped on the left gas tank mount.

OOps, that's Commando info, don't know about ES2.

Some manufacturers (Triumph, BSA, Norton etc.) got into the habit of stamping their engines and frames (or in the case of Commandos on the headstock plate, and also on the gearbox) of their bikes with matching serial numbers.

A bike with non-matching numbers (where they would normally match) can de-value it to a certain extent, as it will have become a mongrel, and some owners or prospective buyers consider this to be important, as it will never be possible to restore a bike with non-matching numbers back to its original 'factory' specification.

shortymonro said:

I have looked in the spots recommended as far as where to find the serial numbers but am just a bit confused as to what means what.

Click to expand...

So, what numbers have you found, and where?