250r has slugish bottom end so i pulled the head and discovered whoever had the bike before me honed and ringed engine. problem is there's about .015 piston to cly wall clearance. so i'm going to buy new piston kit and have it bored. right now it has .010 oversize piston i'm not going to big bore but wondered if anyone offered a piston kit that offered a horsepower increase over std. replacement piston, that actualy works(light weight, flat top, ported)i understand some of these might also require head mods to maintain or increase compression which is ok with me. also i ride and race in the woods and cannot tolerate increased vibration from an out of balance condition. thanks

87 trx250r
93 banshee
87 trx350x

 

I know that Nacs sells boost ported pistons, so does LRD. It is a Wiseco or Niks piston that is modified. They are lighter, since they have less material and supposedly they give more power. Actually, the way they are made, they should help more in the top end though because they keep the intake open longer. That means that you will lose some on the bottom. Trinity sells those flat top Wiseco pistons I think, I don't really know how good they are. If I were you, I would get the head milled and some mild porting to gain the power and not worry so much about the piston.