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Yz 250 cylinder

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Hi, last weekend i went to ride like every weekend and i have some troubles, the first one was that i broke my wiseco piston with 25 hours, because oil seal (left side) failed and I was riding dunes so imagine the results, lean conditions, near the sea my piston get a hole like 4mmx4mm.

This is not a great problem, the big problem comes because either nikasil from cylinder went off under exhaust and on the bottom, something like 10mm x 3mm and under the exhaust something like 40mm x 8mm.

Well everybody probably will say "time to replate" but the problem is that in argentina there are 2 persons that replate and both are on holydays up to 15 of january, and my holydays begins 13 of january.

Someone has a problem like this a put a new piston with out replating? i know that sounds stupid but i have no chance and i need my bike for my holydays...

Thanks

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Sorry to hear that. Living under similar conditions I got used having a spare cylinder, spare crank, spare oil seals, all kind or bearings a lot of pistons and so on. Plus I ride 2 bikes as even with all that precausion I'm forced to have on e bike off for several days when I'm lucky and weeks if not.

As for your problem I know several guys running their 2 strokes with out plating or extremely worn off plating. For me I'd not do that, too much of a risk. Should you try at least smooth out the area where off plating meets plating.

You could take part ith an exchange program USchrome or Millenium offer. Phone in and they send you a cylinder before yours get there. If they do that without you being a customer beforehand is not known to me. But the exchange cylinder way seems to me the best road. Even if it is costly a snapped rod or worse creates more costs.

Good luck

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I don´t know what to do, probably i will buy a cheap piston to ride 15 days, and then going to replate and put a wiseco or oem, think that the worst i can go is to finaly lost all the nikasil and seize, but is one of the faces, the other one it´s nothing happens and i replate and put new top end at the begining of february......

Thanks like ever Arnego you are the only one that knows how is to ride on the 3rd world haha

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No hay problems, I had to use a dremel once or twice so far to smoothen out some little imperfections but they were realy small. It worked OK the cylinder does its job still.

Use a lot of oil, like 20:1 to be safer and where the off plating meets the plating try to make it as smooth as possible so no ring gets stuck on it.

I think there are more than just us 2 of the developing world. :smirk:

Good luck

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The main problem would be a "new" piston\ring catching on the exhaust,the small bridges on the exhaust side are a big issue when worn.(even if you can't see that wear) It will let new rings catch on the edge of the center port. They are the only support to keep that piston from exiting that big port.

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Sorry to hear that. Living under similar conditions I got used having a spare cylinder, spare crank, spare oil seals, all kind or bearings a lot of pistons and so on. Plus I ride 2 bikes as even with all that precausion I'm forced to have on e bike off for several days when I'm lucky and weeks if not.

As for your problem I know several guys running their 2 strokes with out plating or extremely worn off plating. For me I'd not do that, too much of a risk. Should you try at least smooth out the area where off plating meets plating.

You could take part ith an exchange program USchrome or Millenium offer. Phone in and they send you a cylinder before yours get there. If they do that without you being a customer beforehand is not known to me. But the exchange cylinder way seems to me the best road. Even if it is costly a snapped rod or worse creates more costs.

Good luck

Millenium does not have one, I already checked a week ago. And its not exactly an overnight shipment to where you are at.

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Unless you have a lot of cash to spend on a bunch more stuff, I would suggest you don't run it without re-plating.

If a ring catches or the piston seizes you could wind up doing a lot more damage. Broken piston, damaged powervalve, badly cracked / gouged cylinder, broken rod, etc. The fragments from broken rods, pistons and rings can also damage the cylinder head and cases. Those are the worst case scenarios but they are all expensive repairs.

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