You got it. It is JJ Cobas of Spain. I couldn't find much information on his history.
The only article I find was saying:
"Cobas was the innovator of many features of motorcycle design that have become standard on many of today's racing machines. He worked closely with Pons when he won those two 250cc titles for Honda in 1988 and 1989 and has been closely linked with the team's success ever since."
Ahhh , I shouldn't have given a hint so soon
You guys found it immediately
Cobas is the man credited with the change in chassis design that started in the mid 80s.
Until then the bikes had much more conservative geometry, rake angle and rear ride height.
His bikes have won GP championships, and in fact the first GP win of Criville was on a Cobas bike.
He is very highly regarded in the world of racing as a technical expert in design.
He has also built a racing bike with a BMW K engine (the brick), an impossible task for anybody else!