CrabsAndCylinders said:Does anyone know the purpose of the ribs on the pistons, I never found that ribs made much difference but then I thought they went on the inside. Seriously, were they to hold oil onto the piston or what.
Funny, I thought oil was there to reduce friction. Look up JE pistons. They have diagrams on their site that say exactly why the rings are there.teazer said:On that old two stroke design I would suggest that they are there to retain oil rather than reducing friction. At the time a 250cc single was fairly big for a 2 stroke and a 500 twin was really adventurous for the time.
Wiseco et all machine small grooves above the top ring to reduce the flow of combusting gas down to the top ring. They disrupt flow towards the ring.