I'm putting togather the top end of my 95 RM 250 and i've run into a problem. When i put the rings onto the piston, the rings don't go down into the groove far enough to be flush with the sides of the piston. If I tap the rings with a mallet, they go in all the way but they stay stuck in the groove and they have to be pryed out with a screwdriver. It is a standerd size genuine suzuki piston and rings. Is it supposed to do thiis or is something wrong? thanks for the help