I HAVE MANY OTHER PARTS FOR THIS ENGINE NOT LISTED .  PLEASE MESSAGE ME WITH YOUR NEEDED PART NUMBERS.
PISTON 6207-39-2120 GENUINE KOMATSU   +0.25MM   OVERSIZE
 0649T engine BLOCK MARKED S  

 Onan 186-1069
Original Onan  DVB GENERATOR WITH ENGINE BLOCK MARKED "S"   

FITS ONAN KOMATSU 0649T DIESEL GENERATOR ENGINE 

new old stock FROM ONAN CORP

https://issuu.com/engineparts2/docs/onan_komatsu_0649t_diesel_engine_genset_parts_manu

SEE PARTS MANUAL LINK