i am searching for a new CDI unit and the Honda dealer here in Indiana give me the correct part number of 38770-MCJ-671 A & I have been searching Ebay and have found a few but there is a part number below that number on the CDI unit mine for example is 9630-105747 Does anyone know what this second set of numbers under the main pt# means I have found several with 38770-MCJ-671 but diffrent set of numbers under that for example 9630-108553 any ideas

 

usually they are serial update numbers,
so if there was a faulty batch for instance they are able to tell what numbers between need recall.
also they are country units, so for instance here in UK we may have differing CDI units to you in USA, to allow for fuel grade, japan has lower fuel grade so theirs is different and so on and so on.
you need to find one with similar numbers, or at least contact a honda dealer who will give you better info on what the differences would mean should you buy one of different part numbers .
or
you could try source a motad racing unit??