........actually YZ400, the original IT400C only had 61 parts that were not YZ400.
Tank, guards, speedo etc plus the first gear is lower and the fifth gear is higher, also the forks are 40mm longer, other than that, pipe, frame, gear ratios were all the same.......which was a good and bad thing, as unfortunately a lot of them were stripped out and converted back to quasi YZ motocrossers.
Roger