Direct from my 91 kdx 200 manual, head 18lbs, shaft lever mounting 74lbs, inside cylinder standard using two measurements (side by side /front to back)66.016-66.031 and less than .01mm difference between the two, limits 66.10mm or more than .05mm between the two measurements. Piston standard 65.939-65-954mm / limit 65.79mm (measured at 15.5mm up from the bottom of the piston at a right angle to the direction of the piston pin. Piston cylinder clearance .072-.092mm. Piston ring grove clearance standard .025mm-.065mm /limit .18mm. Piston ring end gap standard .15mm -.35mm/limit .70mm. Piston pin and other specs available.