ZEST BOLT Service Manual

Revotron 1.2T 62 D. Cylinder Head Valve Seats : 1. Check the height of each valve seat insert with respect to the cylinder head mating surface. Replace the valve seat if worn beyond the specified limit. 2. Measure the runout of the valve seat with respect to the valve guide axis. Maximum runout is 0.030 mm. Replace or resurface the valve seat(s) as necessary. Cylinder Head Vale Seat Resurfacing : 1. If the valve seat is machinable, use a 45 0 cutter to cut the seat to specifications. Use the appropriate grit to achieve the correct finish on the seat. NOTE • The valve seat must be free from chatter marks, scratches and other specifications. 2. Lap the valves and valve seats to a smooth and even finish using lapping paste and a hand pump grinder or by inserting the valve into the cylinder head and rotating to achieve the proper finish. 3. Coat the valve seat with carbon blue I prussian blue dye and insert the appropriate valve into the cylinder head. 4. Rotate the valve under axial pressure several times and remove from the cylinder head. 5. Inspect the area of contact created by the axial rotation of the valve. • The contact pattern should be equal and unbroken around the circumference of the seat. • The distance from the narrow diameter of the valve seat face to the contact line should be0.5 mm. E. Rocker Arms and Shafts : 1. Inspect the bore of each rocker arm for scoring, signs of excessive heat, cracks or other damage. Replace the rocker arm as necessary. 2. Measure the bore of the rocker arm. The rocker arm bore (I.D.) should be 15.0 +0.011/-0.000 mm. Replace the rocker arm if outside of these specifications. 3. Inspect the screw adjuster on each rocker for excessive wear or damage. Replace as necessary. 4. Inspect both rocker arm shafts for scoring, signs of excessive heat, cracks or other damage. Replace the rocker arm shaft as necessary. 5. Measure the outside diameter (O.D.) along several points of both rocker arm shafts. The rocker arm shaft diameter should be Ø15.0 -0.016/-0.027 mm. Replace the rocker arm shaft 6. Inspect the rocker arm springs. Replace springs which are broken, weak, or showing other signs of damage.