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I've got an 01 yz250f and I disassembled the engine to find out why I had low compression. Turns out I had a leaking exhaust valve but regardless I found a lot of heavy wear on the intake camshaft bearings. Like deep scratches and wear. Looks like a common issue because I found a couple online that are the same way people are trying to sell off for cheap.

 

My question is this: can I put any year head onto my 01 jug? If I was to go 03/04 would that automatically allow me to trash that decompression lever?

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I've got an 01 yz250f and I disassembled the engine to find out why I had low compression. Turns out I had a leaking exhaust valve but regardless I found a lot of heavy wear on the intake camshaft bearings. Like deep scratches and wear. Looks like a common issue because I found a couple online that are the same way people are trying to sell off for cheap.
 
My question is this: can I put any year head onto my 01 jug? If I was to go 03/04 would that automatically allow me to trash that decompression lever?



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Just as I started researching the same thing pertaining to my 2003 WR450F, the ThumperTalk banner popped up with your posting. I encountered the same cam journal wear on mine and sent it off to Engine Dynamics a couple years back. My cylinder head is slightly warped because it was leaking oil between the head and the cylinder right below the exhaust port. Before I ever resurfaced the head with 400 and 600 grit wet sandpaper, I initially just put a new piston and rings in it with new OEM gaskets and assembled to book specifications and it did the same thing again. I still have not reassembled the head to test because I want to have the valves completely done since it is at that point and I want everything done properly anyway. Now, I am about to call Millennium Technologies after having read the writeup about the 4stroke head reconditioning.

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I've got an 01 yz250f and I disassembled the engine to find out why I had low compression. Turns out I had a leaking exhaust valve but regardless I found a lot of heavy wear on the intake camshaft bearings. Like deep scratches and wear. Looks like a common issue because I found a couple online that are the same way people are trying to sell off for cheap.
 
My question is this: can I put any year head onto my 01 jug? If I was to go 03/04 would that automatically allow me to trash that decompression lever?


I reread your post and am trying to interpret that you do have intake cam journal wear, since you mentioned your scratches on the cam. I'm sorry if I read your post wrong.

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Just as I started researching the same thing pertaining to my 2003 WR450F, the ThumperTalk banner popped up with your posting. I encountered the same cam journal wear on mine and sent it off to Engine Dynamics a couple years back. My cylinder head is slightly warped because it was leaking oil between the head and the cylinder right below the exhaust port. Before I ever resurfaced the head with 400 and 600 grit wet sandpaper, I initially just put a new piston and rings in it with new OEM gaskets and assembled to book specifications and it did the same thing again. I still have not reassembled the head to test because I want to have the valves completely done since it is at that point and I want everything done properly anyway. Now, I am about to call Millennium Technologies after having read the writeup about the 4stroke head reconditioning.


Wait so this damage is repairable? On the intake cam journal.

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Engine Dynamics out of California somewhere is the company that does the repair on re-boring the cam journals. I forgot how much I paid when I got mine done. Your cam journals will be mushroomed down and have blued in color as a result of cam journal wear. Look for bluing color on your cam too. If the cam journal metal gets mushroomed down, you won't be able to get your valve buckets out to reshim your valves. Millennium Technologies does not do this work. Type engine dynamics into the ThumperTalk search bar to find out more about Engine Dynamics info.

   

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This probably won't help but I'm running an 04 head on a 06 motor with an 06 piston. You have to check motor mounts on the head, piston to valve clearance, and compression.

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