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I am looking for a new piston kit for the 250. I know most here have 200s and 220s, but is there somewhere to look to see which bore size to get, on the topend or where ever. The bore sizes to choose from are from 67.4 to 68.5. Any help would be appreciated.

Edit pro-x has one that is .0004 or .0008 for "slightly" worn cylinders. What defines slightly worn? I don't think the topend has ever been done, so I don't know if it is slightly worn or not. 4/ ten thousanths doesn't seem alot but if it isn't worn wont that .0004 kind of just make its own room, and is that worse than too loose a piston and pistonslap?

The 250 is plated? They don't 'wear' in the way iron/sleeved cylinders do.

Wiseco doesn't make something to fit? Their website has .pdf catalogs online with all their 'stuff'.

.0004-.0008 isn't squat. 1/2 of one thousandth won't matter one way or another.

IF it's a plated bore and the plating is in good shape, I wouldn't expect the bore to be different from OEM. Barely different anyway.

If you can get a piston for your square (not tapered) bore that gives you no less than .003" (for a forged piston) you should be good. I'd bet most 2-stroke top ends are put together with closer to .005".

A btw..but it would be nice to be able to file-fit the RINGS for a nice snug put-together. I 'spose it happens..but not with MY ring filer!

I put another question in this topic??? Can a kdx 200 be bore to 250 size?

Gionix wrote:I put another question in this topic??? Can a kdx 200 be bore to 250 size?

Don't think so, the max I belive is 225

Not so.

Wibby knows a guy that bored a 200 to something in the 250 range.

To be considered in the process however are a number of items...like...will the KIPS remain, for one. Also, the bigger the 'overbore', the more change will be reflected in the port timing and flow. At SOME point, those changes will become unfixable..and that point will occur sometime after the engine runs fer complete crap.

EG (for example) considers the maximum overbore of the 200 to be 225. That's 'cuz it's his point of view that IS the maximum 'viable'.

Viable being the key word.

(Can)I put another question in this topic??? Can a kdx 200 be bore to 250 size?

You did, so evidently you can. It's just that you shouldn't have.