Is the engines of moto GP two stroke ?

Question

Is the engines of moto GP two stroke ?

Answer 1

They used to be, now the majors use 4 strokes.

Answer 2

Two stroke, 500cc engines were used up to the 2004 season.  2005 and 2006 seasons switched to 1,000cc 4 stokes and the 2007 seasong used 800cc 4stokes.  The current 125cc and 250cc support series still use 2 stoke engines.