2014 siezed with 2 hours

Bought a 2014 yz450f two weeks ago and broke it in for an hour changed the oil, rode another hour and bike seized up, tore it apart and coolant made it into the oil somewhere (oil was super milky)and cam shaft seized against cylinder head. Ordered new camshaft and cylinder head and oil seals for water pump, head gasket was fine, no cracks anywhere. Anyone have a clue what the hells going on?? Yamaha won't do a thing for me

Damn that sucks. You said yamaha wouldn't do anything for you?


I was told no warranty of any kind on competition dirt bikes might be a canadian thing, don't have any pics atm because I work away from home. On top of no warranty the cylinder head is back ordered two weeks. Bikes awesome to ride but kinda second guess it when something like this happens! Makes a guy wonder why there's only a handful of pros riding yamis

The head gaskets are not re-use able, it may look fine but don't re-use it. How bad was the head? Usually they are repairable, check out http://enginedynamics.com.

Not reusing it haha just saying that there was nothing wrong with it and it was not the reason for coolant getting into my oil.

All Yamaha dirt bikes have a 30 day limited warranty. Call your dealer and tell them about it.

Even after the 30 days expires they can still goodwill repairs. That is completely up to them and depends on there amount of warranty work.

If they are low on warranty then they might goodwill it. If they are high on warranty repairs then they may not.

I would get a hold of yamaha direct if the dealer is not wanting to help.

I took the bike apart because yamaha said there was no warranty, and once I knew the problem yamaha said I would have voided the warranty if there was any, so some one lied to me about the warranty, had I known there was warranty I would not have touched it, and now I'm f7&@3" I'll have to put it back together and take it in I guess, they've seen the damaged parts and I gave them a sample of the oil but yamaha is fighting the fact there is a warranty, I'm gonna take this to the bbb and see if they can help me resolve it. Even the dealer couldn't believe yamaha turned it down.

From what I can see in Canada on the yamaha website, the only dirt bikes with warranty are the pw series, TT series and the yz85, everything else you're on your own, the United States could be different.

There have been water pump impeller shafts snapping on the 250F. The part # on the 450 impellers are different by one letter (1SL- vs 1SM-)


The 250 and 450 both share the same "stopper lever assembly" in the shifting assembly and there have been a few new 250f's with destroyed motors due to the bearing coming apart - http://www.thumpertalk.com/topic/1085485-any-14-mechanicals-out-there-to-report/

Edited by Navaho6

The part # on the 450 impellers are different by one letter (1SL- vs 1SM-)



That means nothing.  The part number on the crank and the piston in either engine is different by one letter, too.  Doubt they're interchangeable, unless you know something I don't.


Yamaha uses a "basic number" parts system.  The 5 digit number in the middle of the string describes what the part is.  All water pump impeller shafts are a 12450.  The prefix "1SM" says it's a shaft for a 2014 YZ250F.   The trailing two pairs of characters indicate revisions, alternate sizes, etc.

Haven't heard that, but I'll check it out, should be a recall from yamaha if that's the case

Macbrown is the dealer you bought through in Lethbridge?

Didn't buy it there but I am from lethbridge so that's who is helping me to try and resolve the problem

torkd14 are you from lethbridge?

Damn. I really want a 14 too

Edited by BoSs250f

Ok we'll first off buy a head gasket...no gaskets are reusable and should be replaced! 2nd

Off that totally blows and I would be furious as I am a yami lover.

3rd off you went wrong with the four stroke shoulda got the 250 2 smoke

Just got a 14' yz450f and they offered a 2year full Warranty on the engine/trans to protect from manufactur defects cost me $ 400 this isin the uUSA. I paid almost 9k didn't want to tank any chances

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