08 TXC 510 stuck piston without warning

Yesterday I warmed the bike up and took off from my house and about a mile down the street the engine seized without warning. No noises or anything. Last time I rode it everything sounded and performed fine. The engine was not hot, I could still touch the cylinder with my hand.

Bike is a 2008 TXC 510. I don't know how many off-road miles it has on it but, it only has 1200 street miles.

Any Ideas on how it happened? The oil was a bit low. (.8L) Maybe a quart was not enough? Forgot to check it before I took off.

Any aftermarket pistons available that don't suck? I have not heard good thing about Athena or ProX. The dealer wants $690 for a new piston($342) and new cylinder($348).

I just looked up the oil capacity for the 2008 motors and it is 1.8 US quarts. Looks like you starved the motor for oil. I like the athena pistons and wouldn't hesitate to use one. The pro-x pistons I have seen were ugly though.

If I don't remember wrong the old Engine needed 1,6 L oil.

In your case/location I would contact Bill's about the oem 530 kit.

Kits are back ordered. No ETA. $658. If I could figure out what 100mm piston the kit uses I could just get a piston and send my cylinder out for bore/re nikasil and save $150.

Is it possible to cold seize a 4 stroke? It was 34° outside. I did a 3-4 warm up. Cylinder locked up a minute later. Cylinder still cool to touch. I would think if it ran out of oil the wristpin and bearing would show signs.?

Look under Husqvarna accessories here: Looks to be available.

http://www.halls-cycles.com/check-out-our--xstore

If it starved for oil I would check the crank and main bearings also.

I would tear that motor all the way down and check out the whole engine

What he said.

That piston/cylinder; hard to look at. No here experience with piston seizures, but I would guess the case needs removed and split to check crankshaft and bearings and to remove metal bits from the bottom of the case.

http://supermotojunkie.com/showthread.php?150585-Husky-480-and-530-Big-Bore-Kits

In case you might be interested.

I talked with Toxic. Going to wait for 530 kit. In the meantime I'll pull the rest of the engine down and inspect/replace the bearing. I'm also going to rewind my stator and install my Trail tech rectifier so I can install my LED light bar.

They just priced it, $359 for a piston kit and $23.5 for gaskets seems like a pretty damn good deal

Yes, $599 including boring/re-plating is a good deal.

The oil pump and drive should be carefully inspected as part of your tear down as well.

I agree...something is funny. For sure check that oil pump.

That seizure is massive and I would guess the oil to the crank must be starved too if it was ran out of oil. Even with .8 qts I'd guess the oil pump would still feed...unless you warmed up with a 1 mile wheelie! Did you go from stone cold to WFO? Remember the piston expands faster than the cylinder and it could seize from expansion.

Is there any bluing or other discoloration on the rod big end...pull the wrist pin and see if it is wet with oil.

Are the cam bearings still wet?

The cams and bearings look perfect. No signs of oil starvation. I have not pulled the engine apart any further yet. I will check/replace the oil pump and rod bearing. I'm still leaning on cold seize.( Seized on intake side). Bike was warmed up for 3-4 minutes while I put my gear on,(ambient temp was around 34°F) I then left my house and got on it to pass a car around 1 mile down the road. I was still on it pulling back in my lane when it seized. I could still touch the cylinder with my bare hands so temp was still below 160°F. I will split the case after the 530 kits are done and I have some free time, probably late Feb.

That's scary! Everyone here had some great points on what to check.
I have used CP pistons and Wossner pistons. Both worked great. Wossner was much less expensive.
Cylinder work I have had done by US Chrome. Just about $200 with boring, re plating and shipping.
Seemed to take awhile to run in with some oil loss in the beginning. But then, all ok.

Sounds like oil starvation to me. 0.8L of very cold oil may barely lubricated the forced oil bearings, but will not flow enough to spray out of the rod bearing to lubricate the cylinder walls. Next time, Mobil1 0W40 it up with a SS filter. Allow a longer warm up time too. That way you will get full oil flow, even when it's 34°F out.

Ditto to Timkens comments, a Cold seizure will start with scuffing on both skirts as a result of insufficient Piston to Bore clearance, progressing to heavier scoring on thrust skirt (intake side in this instance) as lubrication breaks down. If scoring is only on thrust side it points to a lack of lubrication.