Yamaha TT600 Engine Serial number
 

I am an owner of a Yamaha TT600 mc 1989 model.
Recently I ordered new sprockets from my lokal Yamaha dealer in Norway and the input for ordering correctly parts was the model year of the bike and the type. I got a wrong frontsprocket but to get a long history short I have now finally got a correct type. BUT the problem is that the engine serial number doesn`t show in the database to Yamaha Norway.
I was told that the mc most likely have the engine replaced and probably a imported one.
My serial number is *4GV-001790*
It`s a one sylinder 595cc Yamaha engine so I was really suprised that they could not fint it in their database.
Have sany others discovered the same problem?
I really want to know exactly what type and year my engine is so I can order spareparts correctly and save me from the trouble I just have had.

4GV is the engine code from a 1993 YAMAHA TT600S, see here: TT 600 S/E

You should have a dark gray engine. You probably have the frame number starting not with 4GV, but with 59X..