250-500cc Should have knocked on wood

Last week I was saying that my WR250 had 300+ hours on it the very next ride I noticed having to use the clutch more often like if riding a 125 also it kicked over easily, not like it's old self which would make you whimper if you weren't wearing good boots. I took it apart today and the piston still looked excellent as did the cylinder but the rings were worn out. An .015 " end gap and little to no tension. Here are some pics
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I did not clean the combustion chamber I simply wiped it with a paper towel. The cyl.had no signs of wear and a perfect cross hatch. I'm replacing the piston just because it owes me nothing and it's showing slight signs of wear on the intake side

These are good solid motors.

Reading the title of post I thought you'd had a catastrophic failure Doug! That's a good run outta that piston. Stick a wossner forged one in there n it'll be good for another 500+ hours!

Can't ask for anything better than that.

Doug you ride it like a girly....where's the signs of 4 corner seizures or heaps of carbon crud on the top of the piston!!! No good mate, giving 2 stroke riders a bad name esp Husqvarna riders, showing us a 300hr bore a piston with very little wear.........

Ya I guess I could have at least turned it into an Amsoil/VP110 fuel infomercial. Truth is I ride like an old man because I am an old man but I still keep up with some of the youngsters in the technical stuff.

Just made me laugh with the first post you sounded disappointed with 300 hours

300 hours aint bad, and the lack of four corner seizures is why its gotten to 300 not 3!
Jettings spot on by all accounts so thats the carbon build up idea ruined.
Those are good looking components for them hours, your right about piston ive seen them shatter just where the lower mark is on the intake.

You did measure across there too see if its still in spec? The bore below intake not piston.

Ok, I got it put back together and it is back to it's old self. I didn't miss the mid-range power until it was gone and now that it's back Woo-hooo! The Wr250 really has a solid and fast engine, it's true that it's a bit heavy but for the dependability and power is worth it.

I ordered a piston from Halls at the beginning of the week and probably would have had it by Friday except for a mix up I caught when they emailed me my receipt... they had me down for a 300 piston which also explained the sticker shock (the 250 piston is about $40 cheaper). It's all good now and thanks to Halls for stocking parts for our Huskys, they are much better than my local YamaKawaHonda dealer.

I ordered the stock factory piston, my cylinder was stamped "C" so I ordered the "C" piston. I didn't have any noises and actually I could have just bought rings because the piston wear was minimal but rings would have probably only got me another 100 hours and I didn't want to risk a blow up. For a factory piston, rings pin & bearing, head "O" rings and a base gasket it was $272.00 which still seems high compared to a Weisco kit for my yz125 @ $150 with gaskets but I guess I could have saved some money by going with a Vertex in the Husky. The reason I went with factory was that I'm hoping to get another 300+ hours out of this one.

Vertex is oem isn't it?

Some years Vertex was stock. The Italians liked to use several suppliers over the years. Some models would actually have 3 different piston brand options. The vertex are good pistons.

Yeh my 300 was vertex

on the 1999- wr250 you could also use a 1998 Suzuki RM 250 or a 1997-01 Honda CR 250 Piston instead.

This shows a Honda CR250 piston https://www.rockymountainatvmc.com/p/3245/32254/Vertex-Piston-Kit-Standard?v=9986 for the 2009 but I didn't see where you could choose the size to the .001 for the A, B, or C cylinder like you can with the factory Husky piston. It is $70 cheaper

i dont know why they didnt show up a b c d pistons- but its like i said- there are some pistons you can just drop in our 250 WRs.