[Product Details] The oil pump is not disassembled. Therefore, there is no specific maintenance method. When the product fails, it is an assembly replacement, but you should replace the two rubber seals of the plunger large and small. If you need a service manual that describes the inspection and adjustment of the oil pump, we will send the URL to you. Oil Seal Large and Small 1 Each Gasket Large and Small 1 Each. [Compatible models] R1-Z TDR250 TZR250 1KT 2XT RZ250 350 DT200WR TZR125 Picture SDR200000 Fits pump Main unit not included.