250-500cc WR300: Do I have to change the piston soon ? (pictures attached)

Hi all,
yesterday I took the pipe out and made some photos of the piston, please have a look:




Bike is a WR300 2010, I bought it second hand and don't really know the hours / kms on it, seems to be the original piston.

I think the piston is not too bad, machining rings are still there on the skirt, there is a spot under the second ring that is shiny.. I think there is some blowby also and a lot of carbon deposits on top of piston and power valve. My jetting was way rich and I'm using a high flashpoint ester oil at 2% mixture.

What are your insights ?
Thanks.

You probably should at least change the rings but here's the deal. When a WR piston fails from fatigue it usually fails on the intake side because the intake port will wear/fatigue the piston skirt until it cracks. That said If you pull the reeds to look at the intake side and pull the pipe to look at the exhaust side and you're going to pull the cyl. for rings you might as well do the piston and start the hour clock over with a fresh piston.

can't really tell... if it would be my bike, i would plan on replacing it proactively and cleaning up all that carbon build up on povervalve. it's easy enough to do.

but you can also check compression and see where it's at.

Is stock piston cast or forged?

Stock should be a cast Vertex...

Thanks all for your inputs !

That amount of blowby looks less than my '06 WR250 which I did a top end on last year. Top ring wear was just under minimum spec and bottom was still in spec. Was running great when I decided to do top end. Had over 10,000 trail miles on it with medium rpm duty. My brother ran his '02 WR to failure with rings totally shot for several years before piston blew. Would be good to do top end but I would run that thing longer if short on funds before replacing piston and rings. Stick with OEM vertex piston from dealer. That cast piston really worked for me. Amsoil Dominator I think was a big part of the engine life

Mine wr piston looks kinda same, not going to chance it yet. Looks good to me

I agree that a top end is safest thing to do. You'll see a nice boost in the low end also.

Looks to me like the piston is getting to hot and burning oil to the side. I go half the race season on one piston, they never have oil burned to them. I have pics on here if you want to check my post's. If you want to verify this look at the underside of the piston crown. If it has oil burnt to it , i got too hot.let me know what you find.