Put rings in wrong after rebuild

[QuadraceYA]

Ive been riding with a friend that recently rebuilt his top-end .

His first try one of the rings were out of place (on top of the little pin that holds them in place ) he Ran it like this for 5- 10 min .... It wore a small ridge down the side of the cylinder .

He tore it down got the ring in the right place and put it back together .

I noticed today when i rode his quad .. it didnt have much compression compared to mine.

So Im wondering if this little ridge could cause it to loose compression.

[98632wr500]

yeah that ridge will cause it to loose compression...how deep is the ridge?...maybe a hone job?...

[250r king]

o hone wont fix the that thats harden steal the ring is bent or left a deep scratch in the sleeve new rings or get it bored lesson learned

[sblt500r]

theres really no way the piston would go in the cylinder if one of the rings was on top of the locating pin. if he did force it in there, he must have wore a deep gouge in the sleeve. was the cylinder bored to the piston in the first place?