TM 9-2815-250-24&P 3-5. CYLINDER HEADS REPAIR (continued). 4. Remove   two   guides   (1)   from   two   recesses   in crankcase (11). 5. Remove  two  O-rings  (10)  from  two  grooves  in each of two guides (1).  Discard O-rings. NOTE · There  are  two  valves,  intake  and exhaust,  in  each  of  two  cylinder heads.    Follow  steps  6  and  7  for each of them. · Part numbers are different for the intake   and   exhaust   valves,   but the  valves  are  removed  the  same way.      This   procedure   describes the removal of an exhaust valve. 6. Using    a    valve    spring    lifter,    compress    valve spring (14) and remove two valve spring retainer locks  (12)  from  valve  spring  (14)  and  exhaust valve (16). 7. Remove valve spring retainer washer (13), valve spring   (14),   and   base   spring   washer(15)   from exhaust  valve  (16).    Remove  exhaust  valve  (16) from bottom of cylinder head (6). b. CLEANING AND INSPECTION 1. Inspect four push rods for bends or wear on four sockets at ends of push rods.  Replace any push rods if bent or if sockets are worn. 2.   Clean    valves    and    valve    seats    with    carbon- removing compound. WARNING Drycleaning  solvent  P-D-680  is  toxic and flammable. Always wear protective   goggles   and   gloves   and use   only   in   a   well-ventilated   area. Avoid   contact   with   skin,   eyes,   and clothes, and DO NOT breathe vapors. DO   NOT   use   near   open   flame   or excessive heat. 3.   Using drycleaning solvent and rag, clean valves, springs, washers, locks, and valve seat. 3-16