The piston pin is locked on both sides by a locking ring made of spring steel. If you replace existing pistons and cylinders, make sure that the rings always have sufficient spring tension; if they do not, they can jump, which can cause very serious damage to the engine. It is advisable to always install new rings to prevent this from happening to your engine.
The rings shown here are designed for 22 mm piston pins and can only be used on the motors mentioned above.
If you want to be 100% sure that the rings can never cause damage, install Teflon piston pin plugs, which are used by professionals (see the Alternatives tab).
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