Engine rebuild Yamaha SR500
Updated: Sep 30
Empty left part of the engine. Start in a clean environment and be sure that all rests of old gaskets are removed.
Place the bearings, use a suitable tubular drift. Use an oven at 100°C for the engine parts and put the bearings in the freezer. This wil help a lot to place te bearings. Do NOT use a paint stripper because local heat could cause distortion of the engine parts.
Do the same with the right engine part.
Place the left engine part on the workbench and be sure that there is an opening when inserting the crankshaft. Use clean engine oil to lubricate all bearings en the crankshaft before you start.
Use a rubber hammer to drive the shaft into the correct position.
Place the two gearshaft assemblies together. Be sure that if the where shims used in the past that they are placed again in the same position an check that a new "o" ring is placed in the groove on one of the two shafts.
Place the gearchange drum, the fork left en the single fork right.
Before placing the right engine part on the left engine part, place a new "o" ring next to the oil pump (yellow arrow). Place the two location dowels (red arrow) left and right on the picture. Apply compound tho the surface.
After that, place the right part on the left part, use a rubber hammer when needed. Check that all shafts are rotating freely. After that, insert the screws (and the cable clips removed during disassembly) and tighten them in a diagonal sequence. After that, check again that all shafts are rotating freely.
Place the stator and secure it with the 3 screws. Secure the cable with the provided clips. Before mounting the rotor, place the woodruff key on the shaft.
Place the rotor, washer and nut. To secure the nut on the exact torque, place a bar trough the eye of the connecting rod and block it with two wood blocks.
Placing the gear shift mechanism (add some grease to push it trough the engine). Spring has to be on the correct place (yellow arrows), the two devices has to correspond like shown (red arrows). In second gear, the marks must be as shown (green arrow). Place the circlip (bleu arrow).
Place also the circlip on the other side of the engine to secure the gear shift mechanism.
Insert the detent plunger, detent spring and housing into the tunnel (yellow arrow).