how to bore a kx250?

My cylinder plating is trashed, so I figure I might as well bore it out rather than get a new cylinder, the bore currently runs at 66.548mm, as compared to the stock bore of 66.4mm. So my question is, what do I need to bore it out to, in order for it to fit a .045" over bored piston..I only only ask because I dont know how much play I need to leave when boring, so that the nickle plating doesn't make it too thin...

It will never work...Have you been running it with the plating worn off for awhile? That cylinder may have to be sleeved to use it now.

My cylinder plating is trashed, so I figure I might as well bore it out rather than get a new cylinder, the bore currently runs at 66.548mm, as compared to the stock bore of 66.4mm. So my question is, what do I need to bore it out to, in order for it to fit a .045" over bored piston..I only only ask because I dont know how much play I need to leave when boring, so that the nickle plating doesn't make it too thin...

lol wut?

 

You cant just bore it out and slap a new piston in it. You need to have it re plated.

lol wut?

 

You cant just bore it out and slap a new piston in it. You need to have it re plated.

  

It will never work...Have you been running it with the plating worn off for awhile? That cylinder may have to be sleeved to use it now.

Sorry, bad wording, I completely get that is has to be re plated haha, infact I have already made a call with the people who will be doing it..so in short, I have the capability of boring/plating..I just dont know how far to go with the bore, so that when I plate it, it will still be the right diameter

Or am I just over thinking this, and re plating it will make very little difference in diameter?

Or am I just over thinking this, and re plating it will make very little difference in diameter?

It'll make a diff but your over thinking it. Go back to a stock bore with the plating, then you have room for wear on the bore later on down the road before it needs plating again. 

Guess I never thought of it that way haha, thanks for the help!

Send the piston to whomever is doing the plating. The plating thickness can vary.        

Most places will replate and hone to stock specs within .00025". But if you want it done absolutely perfect, send them the piston you'll be using, along with the cylinder.

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