KDXRIDER.NET

I just bought my kdx back from a guy I sold it to two months ago, dont ask me why I sold it ,ok Ill tell you , I bought a kx450 f and thought I needed to sell the kdx.Well long story short I still have both bikes but now leaning toward selling 450 so Id like to make the kdx more better.
If I knew how to post pics on here I would.After getting the bike back form this gentleman he had installed a fmf gnarly desert header and a pro circuit type 296 silencer, are these same manufacturer?
anyway Ive heard of the 220s piston having problems so Id like some input on what I should do.Bike always ran perfect when completely stock for one and Id like to keep it that way.Does the cylinder have any of these coating where you cant hone them?any help with info appreciated.

fmf gnarly desert header and a pro circuit type 296 silencer, are these same manufacturer?

one is FMF, and the other is pro circuit...

The piston on 220 are time bomb, replace or you could destroy your engine top and bottom. weisco will work

cylinder has coating, really hard, can't hone that

Out of curiosity - what don't you like about the KX450?

Blaze, I cant say anything bad about th 450,I bought it this winter,and haven't had a chance to ride it.Ive read that these 450 get hot if you dont get them in some moving air,I dont hall ass,Im too responsible now,
Im just worried that the 450 wont match my riding.Not to mention Ive got twice as much in the 450.Ive rode the bike arouned my property abit and its got "IT".I dont think I need " IT".I might just be intimidated by it, Im very comfy on the kdx.

So if your cylinder is worn is it cost effective to bore and have recaoted or what can be done?
The old cylinder still needs to be checked out, bike runs great , Could maby get away with just replacing piston.Waht have others done?

If it's within spec, great. Put a wiseco in it and ride. If it's not, then you'll want to send it to be replated. It's not too expensive, and well worth it. Probably around $175 for just strip and re-plate if no repairs are needed.

If the plating is in good shape you just go over it with a scotch-brite pad and replace the piston, rings, wrist pin, little end bearing, clips, and gaskets.

If its worn through or damaged, you can have it replated, buy a new one, or get a used one and hope it's good.

Ok , this helps juliend and colorado,preciate the info.IVe rebuilt small block chevys but not a 2 stroke with coating.I will inspect the cylinder and see where we are.

take some FOCUS pics of the inside of anything suspicious, makes it easier to help

Dont wait on the piston. I had my 220 for 2 years and never had a problem.I read about the problem on this forum,but figured just one more ride,then one more ride,then one more ride ,its running great. Finally did the top end last weekend after fighting the urge for one more ride. When I pulled off the cylinder,the whole piston skirt fell out and onto the rag that was covering my crank. No damage so I was lucky. Now I tell everyone that I know not to take a chance

Ok, I made time to disassembe top end and piston has been removed.
I dont have any tools to measure cylinder so Im taking to a friend who is a machinist to have him look at it.
Inspected piston and cylinder , cylinder has 5 or 6 vey fine less than hair line scratches vertically on exhaust side of cylinder,you cant feel them with your finger nail though, also around bottom edge of exhaust port some of the plating looks thin just near edge less than a 16th wide following bottom edge for about an inch.At top of cylinder where piston rings do not go plating is thin or chipped back less than 16th around 15 % of circumference.Wrist pin and bearing look beautiful,piston has some wear vertically here and there , not bad though,piston will definitely be replaced.Without seeing pics what is the thought so far?

Well, piston clearance at the bottom of the cylinder skirts is pretty important. If the plating is worn through down there then it's likely the clearance against a new piston would be too great and you'd get piston slap. Let your guy measure the cylinder and get back to us with the numbers.

Ok Im trying photobucket so bare with me .
http://s902.photobucket.com/albums/ac224/clintok1997/

I think it's hard to tell from those pics. In some of the pics it looks great, and in some there are spots that could be glazing or possibly worn plating. Can you try and get a couple well lit (no flash!) shots from the bottom up, sort of an angle so we can see the surface of both of the cylinder skirts? The exhaust ports too!

Can you get a FOCUS pic of this, this looks like the plating is worn...

yeah that's one of the pics I was looking at. Can you feel that spot by the sub exhaust port with your fingernail or is it just buildup from the blowby you were getting on that piston? You could give the cylinder wall a good scrubbing over with wd40 and a scotchbrite pad until the pad comes away clean. That helps remove any glazing or deposits and lets you see the actual condition of the cylinder much more clearly.

Took cylinder and piston to friend , cylinder is within service limit of 69.1mm it measured 69.03mm.The only concern is the plating around top edge of cylinder that is chipped off .The spot that is chippped is above the rings of piston contact and it runs for about an inch aroune top of cylinder,probaly less than a 16th inch wide.also right above the exhaust por t plating is wore or thin about the same.Has anyone had plating that was not perfect like this.Will it hold up ?

Ive decided to have cylinder replated, Im now asking , barring money as the most important issue, whats the bore to be? Standard bore? punch it out? how much? whose good contact to help with plating and correct piston to bore and whats the 225 and 240 kits Ive heard about?whats reliable and dont want to bore too much to where I cant bore again?

most ppl stay with stock bore. bigger bore seems hard to tune, and un-reliable. Want more power, get your carb and head to RB.

juliend had good luck with langcourt http://www.langcourt.com/ You can get the cylinder replated and spec'd to a wiseco piston. I had a quote done and the price for the wiseco piston kit was only $4 more than RM!