250-500cc wr300 2012 it's not a motorcycle

[msmith345]

If you ever have a 2 stroke run away like that just plug the exhaust with a gloved hand and it will kill it quickly.

Or reach in there and unplug the spark plug cap...plenty of room on a WR250/300. Unless it's dieseling already, then that won't work, and you'll have to plug the exhaust.

 

[PowerKord]

If you use racing machinery expect at some time an engine failure. I think the the bike was running way to rich = hotter running = seize.

Running rich does not cause a bike to overheat, running lean causes overheating and seizures.

 

[firecrotch]

If you ever have a 2 stroke run away like that just plug the exhaust with a gloved hand and it will kill it quickly.

Good tip. Though it happened so fast and unexpectantly i was like o @&$@$ and panicked scrambling like a drunken fool. Lol

 

[guscycle]

...don't want to sound like an ass but some time should've been taken to at least find a source of failure before pulling top end off---like doing a leak down test BEFORE tearing it apart would be step one ..no one will be able to diagnos your failure with out having the engine in front of them..in one piece...granted, seeing/reading the seizure points on the cylinder/piston can help identify a problem,it won't answer "why" it happened.I could give you all kinds of scenerios for this but it's not gonna help,so I won't even go there.I work on all makes of bikes and if you think you're the only one that has had a new bike fail,you'd be wrong. I could bash the other brands that have had catastrophic failure when new and dealers that would not warrant repairs,but I won't go there either. I am sorry this had happened to you but jumping to conclusions without proper diagnosis prior to your bashing is unfair.
Try to have a good day,anyway...
Guscycle

 

[Eaglefreek]

Want to hear something funny about my 09 300?
I accidently cinched my throttle cable. Then unbeknownst to me by sheer coincidence kill button wire was severed. So the other day bike started up and immediatly went full throttle from dead cold with no way to shut off other than shutting off gas. So I thought for sure I was gonna destroy the engine.
Instead...bike starts better/runs better now. Perfect compression. I swear by these bikes.

Even if your kill switch was working properly, it probably wouldn't have helped. I've had my throttle stick twice on my bike. Both times the kill switch was ineffective. I click it up to 5th gear, hand on the front brake, foot mashed on the rear brake and let out the clutch slowly and stall it.

 

[broken biker]

Doubt a lean mixture and even advanced IGN timing would cause the power valve bridge to crack like that.
That looks like a repetitive stress issue. did the piston seize? Did it hit the power valve?

A seizure or, maybe if detonation is real bad, then maybe hammered main or rod bearings...not cracks like that.

BTW my WR250 FBF woods cylinder developed the same bridge cracks at the same place after 4 years of hard racing. I had it welded a replated and it is now fine. The FBF cyl has the ports opened more than stock.

I think somthing may be wrong with the machining or casting of that cylinder.

Did you try a new cylinder, and did the same thing happen?

 

[broken biker]

my 2012 WR300 had 3 top end warranty repair seizures in 600kms before the stator was replaced under warranty.the 1st seizure cracked the barrel in the same place as above "not a motorcycle".i agree totally with his post.nothing but trouble.no fun riding when all you think about is when is it going to seize again.variable ignition advance/retard can cause engine damage.the tests of my ignition revealed a cyclic pattern with every kick of 2 or 3 poor sparks,2 or 3 thin pale blue sparks,2 or 3 no sparks etc.when the stator was replaced starting was improved but the spark was still thin pale blue.not happy husky,p.f.g.& trooper lu's

 

[The Swede]

Been riding Husqvarna for 20 years without any problems.