Piston slap

[one1]

I have a 250cc four stroke thats having issues with piston slap. The lower ring is not within spec, it's a bit too much space in the ring gap according to the feeler gauge. I have two jugs and two pistons and theres no reason to buy any more, but i need to solve this issue. The sound is annoying and loud.

My question is should i order new standard rings, try to run oversized rings (first overbore .10) and file the ends down to spec (.04) or take some other measure? The piston matches the jug, but it moves a little inside so i know its worn a little on the jug, but I don't have a good machine shop in town so my only option is to buy a whole new matched jug, piston, rings for $300 or solve this issue with rings.

What do you think will help best? I just got this one jug so i really don't wanna but more.

[90GTVert]

The first thing I would do is take some precision measurements of both the piston and the cylinder bore to get a better picture of what's going on. A micrometer and a dial bore gauge would be great, but you can use a micrometer and a telescoping gauge that's a lot cheaper. You can try to use feeler gauges to get a piston to cylinder clearance figure, but it's not as accurate and it won't tell you exactly what is worn. Best bet is to find a service manual for your engine and follow their procedures. There are common procedures, but sometimes they ask you to measure at specific points.