Opinions from the experienced?

[T.Hopp]

I have a stock 99' 400EX that has a damaged piston and sleve. It will need to be rebored to fix. My question is "What would be the most economical piston size, compresion, and manufacturer to use to get it moving again?" I'm just looking to refresh the motor. I figured I will need piston,rings and circlips. A set of gaskets to seal it back up. Did I miss anything? Thanks for helping!

[04'400ex'er]

are you looking to get alot of performance or just get the bike running again? A 406 would be the first size in bore, and a 416 would be the next step. After that you have the 426 and the 440. If I were you I would get the 416 for performance, but you will still have reliability. A JE piston would be my first choice, but Weisco makes a good piston too. thats up to you.

[roostin_dale]

Go with a 416....

As for brands, get Weisco piston kit (includes rings and clips), and a cometic gasket kit...

[BLEEDRED]

You are on the right track...just make sure you do all your homework before you jump into anything and don't rule out a Ross piston. Seems like it would make sense to go with a 416 if you were staying with the stock sleeve, but since you mentioned that you have to replace the sleeve you could always just go to a 440. But then again you do loose some reliability. Also don't forget to replace all the O rings you encounter while you are at it. Good luck.