How can you figure out the year with just the engine serial number on 750 gsxr?

Answer 1

Engine code

Suzuki uses generally a three-digit engine code starting with a letter and ending with two numbers that reveal the cylinder displacement and type of the engine.

Piston displacement Engine type Design sequence A -49cc B 50-69cc C 70-79cc D 80-89cc E 90-99cc F 100-124cc G 125-149cc H 150-199cc J 200-249cc K 250-399cc M 400-499cc N 500-599cc P 600-699cc R 700-749cc S 750-849cc T 850-999cc U 1000-1099cc V 1100-1199cc W 1200-1299cc X 1300-1399cc Y 1400-1499cc Z 1500-
The same codes are used in the VDS code.
1 Two-stroke, single 2 Two-stroke, twin 3 Two-stroke, triple or four 4 Four-stroke, single 5 Four-stroke, twin 6 - 7 Four-stroke, four
The same codes are used in the VDS code. Unlike type, the sequence number for engine uses a two-digit number starting with 01. Because of the late introduction of this code system, the engines used on several Suzuki models don't use this system. For example, the engine code of the GSX750S is the same as its frame type, GS75X.

Regarding R7** class, the GS750 is thought as the first version of the engine type, but it is not confirmed by Suzuki if they count it as 01. R 7 19
The example above is showing the engine code of the 1990-year's GSX-R750 (R719), the 19th development version of a inline-four four-stroke engine.