1968,
The 92 model is a J1, & the 93 is a J2. The bikes are very similar, but not all parts are the same. An easy way to tell the difference between the two bikes (assuming it has not been changed) is the front brake rotor (disk) on the 92 has 8 floating pins and the 93 & up has 6 floating pins. I hope this useless knowledge I have been carrying around in my head too long helps, but if it does not answer your question let us know & I will research the frame & engine #s as I have a few of the 93s.