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Hi there I have 05 250x that I just put new crank and all new seals with piston rings cylinder and cylinder head. The reason for the rebuild is I bought the bike with a dropped valve and it appears to be caused by oil pressure issues... when I got it assembled the first time I fired it and it was loud and rattled. ( I ran it very little) I pulled the valve cover and it wasn’t getting any oil to the head. As I continue to work my way down the wrist pin jet isn’t shooting oil Either. So I pull the filter and it is soaked in oil. When I pulled it apart it didn’t have a oil pressure relief valve in it so I installed one. I have taken compressed air to all oil passages and they are clear. I tried running it without an oil filter and same issue. It has an aftermarket oil filter cap but I called the guy who owned it before me and he said it was on there the whole time he owned it. I have used all Honda gaskets when assembling And I have so much money in this bike and I’m just at a complete loss. Oil pump is new, oil pump gear is new. Even tried packing it with grease. Has anyone seen an issue like this before? Any help would be appreciated

Welcome to the site !!

Have you checked the Oil Relief Valve ?? , it is located on the back side of the ignition cover right next to the oil filter area , it may be clogged or blocked somehow ...

He stated that the oil relief was missing and installed a new one.

He stated that the oil relief was missing and installed a new one.

My bad ... looks like I missed that somehow .... ....

I guess the next place to look is at the end of the crank where the brass fitting is (Flywheel has to come off) , if that was smashed during installation , it will not seal and you will not have oil pressure to the top end , if that is damaged , as far as I know , the only "fix" is to replace the crank ... There is also a Oil Seal in the ignition cover where that brass fitting goes

Why the relief valve was missing is the clue to the puzzle. Someone removed it in an attempt at to achieve what?

Maybe change the oring Neil, and forgot to put it back.
Is it just the holes in the valve that limits the pressure?
Or does it use a spring to regulate?

It is just O-Rings , Ray , no spring , so yea , it makes no sense why it was removed .... As it seems the prior owner was having oil issues as well