250-500cc WR250 - is my rod bearing gone?????????????

I have been slowly refurbishing my 99' WR250. The engine ran strong, shifted fine, no weird noises before I started this project. The bike was completely gone through front to back, cosmetics, tires, brakes, wheel bearings, plastic refinishing / graphics, etc, etc, etc. I also sent my fork and shocks to WER for a lowering and re-valve. So now finally ready to ride. I take it out today and while test riding it, after a warm up was sitting and adjusting the carb. I start to hear sort of pinging / occasional metallic sound, then it dies and would not restart. It still had good compression. I pull the spark plug and find the ground bent / pushed against the electrode. Is my rod bearing shot?!!! The bike did not overheat. It possibly had a little too much oil in the gear box but that should not cause this effect. I did drain the crankcase oil and there was no excessive metallic particles. Its almost normal to see some very minor sparkles in there, and the oil was clearish / grey which seems normal for this bike (and compared to other posts on crank oil). Is there anyway to tell if the rod bearing is shot without pulling the top end? I'm guessing I have to pull the top end and see if I have rod play? Also, my past experience is with Yamaha and Honda. If I have to pull the engine apart, whats the most difficult part and what special tools are needed for this engine? I'm thinking I have to find a case splitter and see if my flywheel puller is the correct size for this stator. Help! Thanks!

BTW, the almost done bike is in the attached pic...........

It's possible, but you need to pull the top end and see what sort of damage there is. Obviously something went through the motor and hammered the electrode closed, which caused it to stop running.

New reeds?

If you can do a Honda you can do a Husky. The Husky motor is super easy to split.

Any chance that you accidentally had put the wrong spark plug in?

Thanks for all the replies so far. No the wrong plug wasn't in. I had extra plugs but never changed it before yesterday since it ran fine. I also checked the plugs against an application chart. I'm hoping the damage is limited to the top end. The PO had replaced the reeds with Boysen reeds some time back. I have heard there is a life expectancy on them, not sure if a particle got sucked through. I was also contemplating if I had an over heat issue. The radiators were hot but, normal hot. I could touch them with my hand. However, what if the coolant wasn't moving through enough.

When this all happened it was after a 5 minute ride, bike mostly idling so I could adjust the idle level, which crept up a bit after the ride.I then was hearing a periodic, but not constant ping, light metal sound here and there. Yes, that sound could have been "something" being digested, but what? Especially since it wasn't right after start up. I had already gone for a ride.

Yea, the bottom line is I have to pull the top end. I'm just bummed since EVERYTHING else on the bike is new and had some significant rides / outing planned for the bike's refurbishing debut next week!

A buddy if mine had a main jet go through his motor after cleaning the air filter. The main jet was either lying on the work area and got stuck to the filter, then fell in when installing the filter, or his toddler stuck it in the air boot while he was cleaning the filter. We'll never know, but I found the crushed main jet in the pipe.

Even though I knew there was no way the main jet came out and got sucked through the carb and into the engine, I still had to look.

Then again, it might be a rod bearing coming apart. Won't know until you get the top end off.

Good looking piece of equipment...Sooner or later you'll have to pull it apart.
But just for posting purposes, pull the pipe and take a peek in and let us know what you see. Piston still all there?, rings?, scoring on the back wall?, whatever...anything in the pipe?

The ride before mine went out it was acting like it was running out of gas( idling very fast and throbbing like a lawn mower) before the end of the ride, next day I washed the bike and let it dry a while then I started it and let it idle awhile, then rode it to check the mail and while crusing it locked up.

Well when the bottom end failed on my 99 wr 250, it was rebuilt useing a yamaha yz 250 rod kit from pro-x 99 to 09 are all the same so im told.
hope this helps you out

Good info.

Counterfeit bearings are a big problem. Hard to detect. Perhaps your bike was rebuilt and got one.

Okay, see the pic! Pieces of piston were all over the place, which makes me want to split the cases no matter what. The fact that this is on the back skirt makes me think a reed or something sucked in. I didn't pull the reed cage out yet. Big end bearing has a tiny bit of play. I think the spark plug electrode smash was from a piece of piston though. Also when I opened the power valve cover a ton of oily goo poured out. Any clue on that? So besides a bottom end I'm probably going to have to have the cylinder sleeved to swapped. Its actually not too bad, minor scoring, but will have to be measured first.

Wow, nice piston

Ugly!

Can you tell if something went through the motor or the piston skirt just broke? Skirts breaking off there is common for high mileage pistons.

Now you're going to have to pull the crank and clean and inspect it very carefully. I wouldn't even consider reusing the mains and seals, and I'd be very cautious of the lower rod bearing.

It's very possible the cylinder can be re-plated back to stock bore.

So I have been finishing up the riding season on my Honda CRF . I immediately ordered the Pro-X rod kit since I know the Husky cases have to be split, new bearings and seals, etc. I will probably send my crank to Mr. Crankshaft since I heard a few good reviews about him. Not sure what I'm going to do with the cylinder yet. Maybe Eric Gorr will get that job. I'm open to all suggestions on the next steps of this endeavor!