Honda NT650 VIN Desc.
(###RC31#x##000000) 

The first 3 characters are the WMI - World Manufacture identifier 
    JH2 is HONDA motorcycles MANUFACTURED IN JAPAN

The next 5 are the VDS - Vehicle Descriptor section
    RC310 - is an "A Area Code" NT650GT Hawk
    RC311 - is an "AC Area Code" NT650GT Hawk "California Model" 

The next digit is a checksum digit or a letter X

Next Letter is the Year Designator
    J = '88
    K = '89
    L = '90
    M = '91

The next Letter is the Plant Designator
    M = HAMANATSU factory in Japan

The last is the 6 digit VIS - Vehicle Indicator Section