kx sleeveing?

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#1
i got a 88 kx 125 a which has the electrofusion boring or something like that. i hear that if you what to buy a new piston, rings, etc. after your bike "pops" that i also need to resleeve the cylynder becuase of the elctrofusion thing. is this true? and also do you think in years to come i will still be able to buy the sleeves and pistons for this bike even though it will be out dated?
 

Rich Rohrich

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#2
It's possible to have your cylinder replated with a nickel based coating that is much tougher than the original electrofusion coating. You can use standard sized pistons this way. Sleeving is another possibility, but it usually isn't the first choice for most people.
 
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#3
do you mean that i don't have to resleeve with and elctrofusion sleeve every time i change the piston, i can just get a nickle plated sleeve or i need to have my clynder sent in to be plated with a nickle coating.do i only need to resleeve if it is scored or screwed up. also do you think i could buy these in future years (even if the two strokes are banned, do you think they will still make the sleeves, pistons.etc.. for them ?)
 
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#5
but do i need to resleeve it every time i change the piston? if i do can i buy a stronger sleeve than the elctrofusion?
 

Rich Rohrich

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#6
If you replate it with a coating similar to the original electrofusion all you have to do is replace pistons and rings for maintenance, the coating is very hard and will not wear.

If you sleeve it you'll have to have the sleeve rebored (machined) because the sleeve will wear out along with the piston and rings.
 
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#7
hey sorry if im irretating you guys but i dont know much about the top end of the motor. :ugg: But to get this clear, when i change my piston and rings do i need to change anything else if the rest of the top end looks good? Its just that i heard that only these KX bikes from certain years have an elctrofusion bore or something and every time i change the piston and rings i would need to resleeve the cylynder every time.
 
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#8
I think the issue is that the electrofusion plating will flake. When you change your piston and rings, check the condition of the cylinder. You only need to have it replated if you see a problem like scoring or flaking.

I'm sure someone will correct me if I'm wrong here.
 

viking20

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#9
Just have it re-plated , and it will last for a long time.The only thing you normally do when changing piston , is to lightly hone the cylinder.This is to remove the "glazing" on the cyl wall , so the new ring(s) seats properly....
 

Rich Rohrich

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#10
MarkSims said:
I think the issue is that the electrofusion plating will flake. When you change your piston and rings, check the condition of the cylinder. You only need to have it replated if you see a problem like scoring or flaking.
Mark summed it up perfectly. :thumb:
 
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#11
Modern dirtbikes do not have sleeves. A sleeve is a round chunk of metal that sits in the cylinder that can be bored oversize when it wears. Modern dirtbikes have the aluminum cylinder walls plated with Nickel or Chrome or a combination thereof called NiChrom. This plating is much stronger and lasts for a very long time. As long as it looks ok when you replace the piston, you can keep using it.

certain years of kx's have their cylinders plated with something else through a process called electrofusion. It has a tendancy to flake away, so eventually needs to be replaced. If it is bad, you can either have a sleeve inserted into the cylinder, or have it plated with NiChrom. The sleeve option does not transfer heat as well, but allows you to overbore it when it wears (which is MUCH cheaper.) If you send it in to get plated, expect to pay upwards of $200. Plating transfers heat better than the sleeve, and lasts for a very long time, but cannot be overbored. Once it wears out, you have to send it back in to get replated again.

Some of this info may be slightly off, due to the fact that I have never owned a bike with a plated cylinder, and I learned all this while researching on a new bike I wanted to get, but most of it should be 100% correct...