NOTE: If you do not follow this procedure, you run the risk of warping the cylinder head.
4. Now remove the cylinder head nuts and washers and lift off the cylinder head gasket. Usually, the aluminum head gasket will stick to the head upon removal, so just pry it loose with your fingers.
5. Remove the cylinder slowly enough so as not to break the cylinder base gasket, being careful to support the piston so that it cannot fall against the engine cases or cylinder studs. You do not want to use the base gasket over again, but if you are not disassembling the lower end of the engine, you must be careful to keep the gasket from breaking, as a piece from it or a piece of dirt on it might fall into the crankcase.
NOTE: If you are disassembling an engine that has been run under extremely dirty or moist conditions, and you intend to remove only the cylinder and piston for repair, turn the engine upside-down for removal of the cylinder. Engines run under these conditions sometimes accumulate mud and rust in the holes through which the cylinder studs pass. If you remove the cylinder right side up, this dirt will fall in the crankcase and main bearing oil passages.
6. Wrap a clean shop rag around the connecting rod so that it covers the entire crankcase opening. This is just to prevent the wristpin clips from falling into the crankcase while you are removing them. Using a pair of needle nose pliers, remove the clips from the piston and discard them. It is not advisable to reuse the wristpin clips.
7. Butt the OSSA wristpin drift, part No. 999-202 against one end of the wristpin. Support the piston with one hand to prevent any side loading of the connecting rod. With the palm of the other hand, push against the wristpin guide to slide the wristpin out of the piston (Fig. 2). If the wristpin is tight and will
not move, remove the guide and use a wristpin pushing tool to remove the wristpin (Fig. 3). Do not attempt to remove the wristpin by hitting the guide with a mallet. Under normal operating conditions, the connecting rod does not receive any side loading, therefore, it is not designed to withstand them. Even gentle tapping against the wristpin guide with a mallet could bend the rod or mar the rod bearing.
8. Remove the wristpin guide (or driver) from the piston. Remove the
piston and the needle bearing from the rod.