09 yz450f headgasket or other problem?

7 replies to this topic
  • muuurph

Posted June 03, 2013 - 03:35 PM


I recently bought an 09 yz450f, I use it on the trails and pits, this past weekend we headed in a different direction across maine, ended up being 4 hours of muddy trails and not going very fast, if I had a choice at the time or knew it wasn't going to get better I would've headed home, I have been on crf450's my whole life, most I've had from slow riding is a little antifreeze out of the overflow...

So, riding, finially hit a dirt road and was cruising my motor started getting ticky, shut it off and checked the oil, had water in it for sure, under the fill cap and a little on the dipstick, but it barely hit the dipstick, I had done an amsoil oil change that morning and it was topped off...

I attached a photo of what my oil looked like, I must have pulled out close to a quart anyways, threw cheap oil in it and started it, after 5 seconds the tick went away, i drained it after it warmed up, it was still very watery, I had a lot of air blowing out of the valve cover blowby hose, had the radiator cap off but it heated up quick so I threw it on, just trying to flush it out now, if I find no answer Ill rie it around the house this weekend and see what it turns out to be, and if it matters, there is only 11 hours on the bike, new filter with outerwears, and oil changes done every 5 hours or so.

Thanks if anyone has experianced this or can head me in the right direction.

  • muuurph

Posted June 03, 2013 - 03:39 PM


also, my antifreeze level was just covering the cooling fins, maybe a little lower then normal.

Attached Thumbnails

  • yz450.jpeg

  • muuurph

Posted June 03, 2013 - 03:48 PM


So I have been reading through the FAQ, answered why the water is in the block, toward the end of the day with a noisy motor, the breather tube was definitely under water, it would not start over I must have kicked it over 10 times and the bike always starts by the 3rd kick, so that must have been why.

But, I still have the question that is there supposed to be an abundence of air flowing out of the breather tube, and it sucks when you cover it, and if you rev the bike it pretty much goes away?

  • etuke

Posted June 03, 2013 - 03:59 PM


I re routed my breather hose a soon as I got it,ran 1 to the air box with a tee and the other down by the bottom of the shock.

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  • muuurph

Posted June 03, 2013 - 04:08 PM


When it's running does it blow a constant air out? I'd like to run mine right into the airbox blowing out the bottom, that way it never gets water in it again, if that's my problem

  • muuurph

Posted June 03, 2013 - 04:12 PM


This thread should just be deleted, I guess I panicked and should've just read up on my questions. Going to re route my breather and keep flushing oil through my motor, and stay away from mud next time.

  • grayracer513

Posted June 04, 2013 - 06:23 AM


The piston moves 450cc of air on both sides of the crown. When it comes down, 450cc goes out the breather. When it goes back up, 450cc runs back into the crankcase. When it's running, it doesn't have time to move all that air before the pressure reverses again, but at cranking speeds it does.

  • muuurph

Posted June 04, 2013 - 03:08 PM


new problem, i have run 4 liters of oil through the bike, letting it warm up and draining it, oil coes out each plug as normal, it seemed that there wasn't as much oil coming out of the trans side, and wether you put a liter in, or liter and a half, it wont show on the dipstick, i made sure the oil hose running from the top of the case to the tranny side wasn't clogged, but something else is, the motor is still a little noisy, the filter had mud bog wood and other particles in it, a pile of it, i would imagine the oil pick up screen is clogged, I plan on pulling each case cover off and brake cleaning the hell out of it, along with the pick up tube, (hopeing the pick up tube is under the flywheel like other bikes). Where are the major ports for oil going to the head and to each side of the case? would like to blow air through everything and brake clean to get it all out. Thanks again guys.

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