My son brought home a 450f basket case!

My son brought home a 2003 yz 450f. The motor was locked up! We pulled the valve cover to find a broken valve retainer. The valve dropped and would not allow the piston to come up. The good thing is the bottom end seems to be fine. But the head is beat up. My son doesn't have a lot of money to replace the head with a new one. so we are looking for a used one. My question is what other model's or year's 450 heads are interchangeable on the 450f ? Thanks in advance Sean.

Its not going to be a cheap fix. A used bare head head is $300.

Its not going to be a cheap fix. A used bare head head is $300.

Im sure it wont. We will be looking for a used head. that is why im looking to find out what heads are interchangeable with the 2003 450f Thanks sean

if i had to guess,it would be 03-05.i say this because the 03-05 yz250f parts are interchangeable. 03-05 they were basically the same bike for the 250f's

if i had to guess,it would be 03-05.i say this because the 03-05 yz250f parts are interchangeable. 03-05 they were basically the same bike for the 250f's

Thanks for the input. Do you know if the WR 450 head will work on the 450f ?

Thanks for the input. Do you know if the WR 450 head will work on the 450f ?

hmmm i dont know about that one??if i had to guess,i would say no

Yes,the YZ and WR head have the same part number.

Wags, is this your head?

Nope I was just playing around on ebay same time as I saw you thread and this was on my screen

When you say the head is beat up, how beat up? A few marks with no cracks can often be run. I'd have a shop check it for cracks.

Try to get a head complete with the cam caps if possible.

Try to get a head complete with the cam caps if possible.
How about this: Don't buy one without the caps. They're too big for a paper weight, and not heavy enough to be a good door stop.

Your head is probably a lot more fixable than you think, and probably for the same or less money as a used one you'd need to spend money on anyway. Do yourself a favor and contact Engine Dynamics first.

How about this: Don't buy one without the caps. They're too big for a paper weight, and not heavy enough to be a good door stop.

Your head is probably a lot more fixable than you think, and probably for the same or less money as a used one you'd need to spend money on anyway. Do yourself a favor and contact Engine Dynamics first.

gray racer thanks for the link ill check them out

Ok I found a 04 yfz quad head complete. does anyone know if this will cross over to a 03 yz 450f? Thanks again in advance!

Ok I found a 04 yfz quad head complete. does anyone know if this will cross over to a 03 yz 450f? Thanks again in advance!

I believe it does. If I remember correctly you will have to swap out the water spigot on the front, but other than that it should be the same.

I believe it does. If I remember correctly you will have to swap out the water spigot on the front, but other than that it should be the same.

Cool thanks for the input

Same part number. No question.

You probably do not want to hear this but.......I would worry about the crank being damaged. Crunched needle bearing coming apart in a couple hours would trash the entire motor again

You probably do not want to hear this but.......I would worry about the crank being damaged. Crunched needle bearing coming apart in a couple hours would trash the entire motor again

Where would the needle bearings come from if it broke a valve spring retainer cap?

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