A video I did some years back on installing a Piston Pin retaining Clip on a GP123cc. its important not to bend the C Clips and ensure they snap into place. this ensures they retain their tension and stay in the groove in the piston. Loosely fitted and they will slowly move and rotate inside the groove, until the groove wears enough for them to fall out, with disastrous consequences.
Thanks to GP engines for their support and providing us with the highest quality engines!