piston pin ? is it important

[Rconce01]

i pulled apart my little china 80cc for some porting based on this thread. http://www.motoredbikes.com/showthread.php?t=5516&page=8

Once i removed the piston i noticed the pin that keeps the bottom ring in its place is flattened out and is allowing the ring to rotate freely on the piston. The top ring is fine it has its pin and doesn't rotate.

any idea how to fix this. i suppose i can drill the pin out and wedge a small piece of utility wire in its place??

 

[Al.Fisherman]

i pulled apart my little china 80cc for some porting based on this thread. http://www.motoredbikes.com/showthread.php?t=5516&page=8

Once i removed the piston i noticed the pin that keeps the bottom ring in its place is flattened out and is allowing the ring to rotate freely on the piston. The top ring is fine it has its pin and doesn't rotate.

any idea how to fix this. i suppose i can drill the pin out and wedge a small piece of utility wire in its place??

Really no need to. Just make sure that the ring ends are not stacked on top of one another. I'd just install them 180 degrees apart. Just make sure that there is NONE of the pin behind the ring while installing...don't force rings into the cylinder. These engines are the only engines I've ever seen with pins like they have. There may be others but not many.

 

[Rconce01]

ok excellent thanks!

 

[GearNut]

It is common for 2-strokes to have locating pins in the piston ring groves. They are there to prevent the ring from rotating around and one of the ring ends snagging on a cylinder port. As logical as this is, not all 2-strokes have them.