How to SUCCESSFULLY Re-assemble your Engine The re-assembly of your engine MUST be done correctly, and you have to be GENTILE! Do not force any parts together! There are several things you need to pay particular attention to, in order to re-assemble it correctly. (1) Make sure the piston is turned the proper direction. Look at the top of the piston and you'll see a date code. You may have to clean the top of the piston off. The date code is pointed towards the carb, or front of the engine. Also, make sure the piston ring is properly aligned up with the anti-rotation pin.
(2) Insert the piston & rod in the crankcase and gently secrure the rod on the crankpin.
NOTE: THIS IS THE MOST CRITICAL PART! Secure the rod on the crankpin with the piston at Top Dead Center as shown in the photo. (3) Check the Piston Ring and make sure the ring is aligned up with the Anti-rotation pin. (4) Make sure the Date Code is facing the front of the engine!. (5) The ring will be loose, but that's OK. If everything is aligned up correctly, insert the sleeve over the piston while GENTLY and SLIGHTLY rotating the sleeve back & forth. The sleeve will align and compress the ring and slide down over the piston & ring. Keep the piston at TOP dead CENTER during this process. (6) Have the Exhaust port on the sleeve reasonably aligned with the exhaust port on the crankcase. This will prevent the ring from getting hung in a port.
(7) Make sure the piston is in the sleeve. Slide the sleeve down as far as it will go while holding the piston at top dead center. The sleeve will likely stop before it reaches bottom, and that's OK. Warm up the crankcase jug with a torch just enough for the sleeve to slip all the way down. (8) Once it sleeve is all the way down, rotate the piston to BOTTOM DEAD CENTER and check the EXHAUST PORT alignment. Rotate the sleeve as needed to get a perfect Exhaust alignment. You may have to warm up the crankcase again.
Let it cool down. Liberally oil the ALL internal parts then rotate the crankshaft and observe the piston motion for smoothness. If everything is smooth, install the backplate.
With the backplate installed rotate the engine and check for rubbing. If the crankshaft rubs the backplate, then tap the crankshaft in further into the crankcase. If everything is OK, complete the assembly. CONGRATULATIONS!
You have successfully finished your engine... |
