While looking around at parts,  I see references to a numbering scheme that I do not recognize nor can I cross reference.  I do not know what it means and how to interpret it.   For Example, in the following listing title:

'Yamaha DT250 Enduro YM235B. Engine top end cylinder crankshaft head piston"

What is the significance of YM235B?    what information is this suppose to be telling me?   what does it match up to and on what year bike?

john

If you're seeing that on ebay check the seller fine print. Usually those goofy numbers are their bin locations in their warehouse and have zero to do with part identification. 

In other words those numbers only mean something to seller.

Looks Like your right.   All these codes I have been seeing appear to be from the same seller.    One thing to use it for, if you search on the code, you get all the parts off of the same bike,   at least for this seller.