Engine body Assembly of piston, piston rings and connecting rod 6. Note: Check that pistons of the correct oversize are used if the cylinders have been milled to oversize. 7. Check the big-end clearance. See "Inspection of crankshaft" and "Inspection of main and big-end bearings" on pages 46 and 47. Check the piston ring gap in the cylinder bore (Fig. 41 on page 35) and that the rings do not jam in the piston ring grooves. 1. Fit one circlip in the piston. 2. Oil in the gudgeon pin and bushing. Fig. 49. Assembly of piston and connecting rod ( MD2010, MD2020) 1. TOP marking 2. Oil scraper with expander spring (MD2O10-2030) Fig. 51. Placement of piston rings Fig. 50.
Assembly of piston and connecting rod ( MD2030, MD2040) 3. Heat up the piston to approx. 100°C (212°F). Place the piston and connecting rod so that the markings correspond with Fig. 49 or 50. MD2O10, MD2020: With the marking on the con- necting rod's side upwards the arrow on the piston top should be turned in the same direction as per Fig. 49. Fig. 52. Fitting of oil ring (MD2040) MD2030, MD2040: The marking on the connecting rod and the "SHIBAURA" mark in the piston should be turned in the same direction as per Fig. 50. 1. Top scraper ring 3. Bottom scraper ring 2. Expander Push in the gudgeon pin. 8. Fit the piston rings on the piston with a piston ring tong. NOTE!
The gudgeon pin should be able to be pressed in easily. It must not be knocked in. MD2O10, MD2020, MD2030 : Fit the oil ring first ( with the marking turned upwards). The opening in the expander spring should be placed 180° from the oil ring gap. Note: The rings should be turned as per Fig. 51. 4. Fit the other circlip. 5. Check that the connecting rod goes easily in the gudgeon pin bearing. 38