KDX220 Woosner piston ring setup

[Slick]

This might be a stupid question but I would hate to start this project with a stupid mistake. I have a 97 220 and am doing a fresh top end rebuild. I had a shop hone the cylinder, measure the cylinder and order a Wossner piston and rings. The rings come with a stamping on them. N100. Do they get installed with the stamp upwards? I am guessing so but I want to make sure. It didn't come with instructions and I couldn't find anything on their website. I have searched here and not coming up with anything. It's been 30 plus years since I have been in a two stroke so I am taking it slow.

[KDXGarage]

Does your cylinder have a sleeve? The stock plated cylinder should never ever be honed.

[Chuck78]

Does your cylinder have a sleeve? The stock plated cylinder should never ever be honed.

While my first reaction was to cringe at the thought, assuming it was a ball hone or other typically available hone intended for steel/iron/sleeved cylinder bores, there are precision diamond hones (which are very expensive) made specifically for Nikasil, and generally only possessed by shops, so there's always the slightest chance the shop actually used the correct type of hone.

Nikasil is a rather thin layer though, so honing it with something that can properly cut it certainly can go wrong rather quickly, requiring a re-plate job. I believe a diamond hone is intended to only make several quick passes through a Nikasil-plated cylinder.


I was talking to another fella just recently that expanded my knowledge base a bit for me. He said that diamond hones take the material off so fast that he exclusively uses some other types of hones, I'll just quote him for lack of me researching his recommendations:

"use Levigated Alumina and Aluminum Oxide hones on plated cylinders, doesn't touch the Nikasil. Using Levigated Alumina. you can hone brass and aluminum with as well. Diamond hones take so much material."

He advises that he exclusively uses hones from BrushResearch.com

I personally use a Scotch Brite abrasive pad by hand for deglazing. If I think the plating is worn to the point of the bore being slightly out of round, I'll send it to Boyko Racing, as Ted Boyko has a diamond hone for his precision honing machine, and if it's able to be squared up, he'll do it, and then it'll be suitable for a Wossner B or C-sized piston (but never a Wiseco, as they not only are inaccurately sized and with a worsening reputation in the last several years since Race Winning Brands bought out Wiseco, ProX and others and sent their quality control down the toilet, but also, they are only sold in advertised A-size for a brand new bore spec inside diameter).


I was thinking about making up a slit mandrel to slip a long scotch brite pad through in order to do some faster deglazing of plated cylinders, as I've seen this done before.

[KDXGarage]

The owner's manuals state that the stock Electrofusion cylinder should not be honed. Stock is Electrofusion, not Nikasil / nickel silicon carbide.

Diamond hones sound great during the replating process, as they want to remove the new plating down to a certain size, producing cross-hatching. It does not sound so great to use to remove glazing, as it once again removes plating.

[Slick]

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Does your cylinder have a sleeve? The stock plated cylinder should never ever be honed.

I didn't consider that. I brought it to the local repair shop (they don't specialize in any one brand but work on a lot of different machines ranging from jet skis, snowmobiles and motorcycles.) to have the measure the diameter of the cylinder so the right sized piston and rings could be ordered. I had them order the piston and rings. They knew what machine it was so I figured they knew if it could be honed. I attached three pictures and from what I know about sleeves it doesn't appear to me that it is sleeved. The third picture is of the Wossner piston and rings that they ordered. I don't know the history of the bike since I have only had a little over a year but disassembling it I was under the impression it was all stock. Nothing has been done to the exhaust or intake so I was thinking everything was stock.

[KDXGarage]

It is hard for me to see on those pictures. See if there are any chipped edges around the ports.

Electrosuion coated cylinders do not have strong cross hatching like most other cylinders.

Hopefully they took it gentle. Maybe they used one of the brush types that is for deglazing.

On the ring ends, do they have an arced end? Is there a piston ring pin in the piston that would match up to it?

[Slick]

It is hard for me to see on those pictures. See if there are any chipped edges around the ports.

Electrosuion coated cylinders do not have strong cross hatching like most other cylinders.

Hopefully they took it gentle. Maybe they used one of the brush types that is for deglazing.

On the ring ends, do they have an arced end? Is there a piston ring pin in the piston that would match up to it?

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Now you have me thinking. I want to do it right. Considering sending the cylinder out and have it sleeved. I would like to use the purchased piston and rings though. Would that be a better approach?