2003 Kawasaki KLF250 Service Manual., Page 88Get this manual
ENGINE TOP END 4-29 Valves, Guides, Seats, Springs, Oil Seals
If the seat width is too wide, make the 60 [A] grind described belowIf the seat width is within the specified range, lap the valve to the seat as described belowGrind the seat at 60 angle until the seat width is within the specified rangeTo make the 60 grind, fit 60 cutter into the holder, and slide it into the valve guideTurn the holder, while pressing down lightlyAfter making the 60 grind, return to the seat width measurement step aboveCorrect Width [B]