proof of age

hi I'm trying to find out the age of my kz400 but not getting very far with it, I have tried kawasaki uk and they got in contact with japan and they said its not original? the bike was shipped from the US in the 80s so I thought it might be made there not japan, I need to know the correct age so I can apply for historic class tax with the DVLA, I know the frame number and engine does not match because I have totally rebuilt and customized the hell out of it, I think its a 1975 D4 because all the parts I have been getting for it fit for that year, I just need proof of age, hope you can help me out. The frame number is K4E 116744 and frame is K4-027413 Thanks Pete

That's a custom build. It starts ageing when you put it on the road.
Steve

From info from this site kz400.com/ the frame number you posted would indicate it is a 1974 frame. As it appears from 1975 on the frame number began with K4S. Since your frame does not have the S it appears to me that it is a 74 frame.

I believe you will find the frame is from a 1975 KZ400-D2. Take a look at the link below, and look at the specs for the 1975 KZ400-D2. Notice the beginning frame number for the 1975 KZ400-D2 is K4-013800. Now take a look at that same link at the specs for the 1976 KZ400-D3. Notice the beginning frame number for the for the 1976 KZ400-D3 is K4-044601. Since your frame number is K4-027413 it was made after the first 1975 D2 frame but before the first 1976 D3 frame, so to me that makes it a 1975 KZ400-D2 frame. Ed

www.kz400.com/ModelidentificationFrameset.html