Time for a Replate?

[Trykman]

After close examination of my cylinder and piston, I found this:

So what do you guys think? I'm almost positive I'm due for a replate. I'm likely getting a top end kit for Xmas so I want to be sure my cylinder is OK.

Also, who do you recomend for plating? I've heard good things about USChrome, and they're the cheapest I've found.

[Mark6299]

I think that piston looks pretty good. Possibly a little lean on the jetting. I would recommend Eric Gore for your jug. I think he uses Millennium Plating for the plating work. He will give you really good service too. Look him up. He is a big name in the moto world. He will take apart you power valve, clean it, reinstall it and set it up proper as well as machine you head for proper squish and cc the dome for the fuel you use. Very reasonable price and rather quick too. You could always go big bore too for just a little more.

I sent in my YZ250 jug, thinking I needed a replate too. He evaluated it, cleaned it up and did the head for $25. He told me my jug just needed some cleaning up and that it was fine. I sent him my old and new piston too. He will not screw you. Or go with US Chrome. Let us know what you end up doing.

[Trykman]

I think that piston looks pretty good. Possibly a little lean on the jetting. I would recommend Eric Gore for your jug. I think he uses Millennium Plating for the plating work. He will give you really good service too. Look him up. He is a big name in the moto world. He will take apart you power valve, clean it, reinstall it and set it up proper as well as machine you head for proper squish and cc the dome for the fuel you use. Very reasonable price and rather quick too. You could always go big bore too for just a little more.

I sent in my YZ250 jug, thinking I needed a replate too. He evaluated it, cleaned it up and did the head for $25. He told me my jug just needed some cleaning up and that it was fine. I sent him my old and new piston too. He will not screw you. Or go with US Chrome. Let us know what you end up doing.

Thanks for the quick reply. I have heard of Eric Gorr and he was one of my first choices. Maybe I should contact him, and see what he thinks about it and go from there?

[GMO397]

Thanks for the quick reply. I have heard of Eric Gorr and he was one of my first choices. Maybe I should contact him, and see what he thinks about it and go from there?

Yes, I would send that to eric. Cylinder definitely needs repalted.

The piston looks pretty good for side wear. But the crown shows a lot of piston wash: rich. But the bottom of the crown shows a large burn area: lean. Have eric check the cylidner and head for squareness. I would throw in new crank seals also because of the rich and lean piston qualities, possible air leak. Also I would do a leak down test once you've reassembled all of it to ensure your engine is air tight.

[cr250_gus]

Go to your local machine shop and ask they if they can re-hone it with a new piston, same size as now, they will tell you if you can re-hone, or need re-plate

[Trykman]

Yes, I would send that to eric. Cylinder definitely needs repalted.

The piston looks pretty good for side wear. But the crown shows a lot of piston wash: rich. But the bottom of the crown shows a large burn area: lean. Have eric check the cylidner and head for squareness. I would throw in new crank seals also because of the rich and lean piston qualities, possible air leak. Also I would do a leak down test once you've reassembled all of it to ensure your engine is air tight.

I guess I'll do that. I believe that the burning/piston wash is because that is the original piston that came with the bike. The guy who owned this bike before me only replaced the ring and sometimes the cylinder because it was raced heavily.