07 YZ450 cyl head...other years fit?


8 replies to this topic
  • tntmo

Posted September 16, 2010 - 05:23 PM

#1

My buddies 2007 YZ450F had a somewhat catastrophic cylinder head failure, I haven't had a chance to check it out yet but it sounds like he has at least three bent valves and a shim bucket that is broke in half along with some other assorted damage.

I'm scrubbing Ebay looking for a replacement for now, but need to know which year model YZ450F heads will fit the 2007? Which year WR450F cylinder heads? Will YFZ450 cylinder heads from the quad fit, and from which years?

Thanks.

  • KJ790

Posted September 16, 2010 - 05:31 PM

#2

06-09 YZ450F heads will fit, I believe 07-10 WR450F heads will fit, but I'm not positive. The quad is tricky because the YFZ450 uses the old style head (like the 03-05 YZ450F), but I believe the YFZ450R uses the same head as your buddy's machine.

If it is just bent valves and a cracked bucket, it would probably be easier to just work with the head you have, odds are the damage is not to the point where the head is junk. I just fixed a YZ250F with the same problem and it cost me under $400 and now it has an all new valve train. With an ebay head you don't know what you are getting, or how long it has really been used and/or abused.

  • tntmo

Posted September 16, 2010 - 05:43 PM

#3

Who did you go through to have it repaired? I was looking at Milennium Technologies website, looks like they could repair it. From what he told me the area around the center bucket is messed up a bit.

  • KJ790

Posted September 16, 2010 - 07:21 PM

#4

The head itself on the one I had was not damaged. The valves were bent and two lifters were cracked and wedged in the bores. I welded a rod to the top of the lifters and pulled them out, luckily they were not wedged very hard and the bores were not damaged. I polished the bores by hand to make sure they weren't scratched, then measured everything. Pulled out the old valves, changed the guides, got the seats recut, and put in all new valves, valve seals, springs, retainers, keepers, and replaced the buckets that were broken. I got all of the OEM parts from East Toledo Honda, they seem to be one of the cheapest when it comes to OEM Yamaha parts.

If your valves are just bent then the head shouldn't need repair unless the bores where the buckets go are damaged. You should change the guides though to be safe.

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  • tntmo

Posted September 16, 2010 - 07:29 PM

#5

He just dropped the head off at work with me. It looks like the center bucket bore is a bit messed up and the bucket is cracked in half and wedged into the bore. I'm going to pull all the intake valves tonight, they are all bent. Then I will see if one of the other buckets will fit into the center bore. I'll call around and see who, if anyone, can repair this sthing.

  • grayracer513

Posted September 16, 2010 - 08:00 PM

#6

Also check Engine Dynamics. The '08 and later Quad head fits. The difference you can spot is that yours has no drilled and threaded port to attach an oil line to at the right rear of the head. The older Gen1 450 has that.

  • tntmo

Posted September 16, 2010 - 08:01 PM

#7

Also check Engine Dynamics. The '09 and later YFZR Quad head fits. The difference you can spot is that yours has no drilled and threaded port to attach an oil line to at the right rear of the head. The older Gen1 450 has that.



So 08-10 quad should fit?

  • grayracer513

Posted September 16, 2010 - 08:28 PM

#8

Scratch that. On Double checking, only the '09 and later YFZ450R models have the right head.

  • tntmo

Posted September 16, 2010 - 08:52 PM

#9

Scratch that. On Double checking, only the '09 and later YFZ450R models have the right head.


Thanks. Looks like just the parts I see that need to be replaced at this point will be about $250. Yamaha wants about $50 each for valves.





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