[timmy2648]

I have a crf250r with what I have been told is a blown motor but it has just been rebuilt 3 months ago and I don't ride it harshly like I don't get that hard on the throttle because I am still getting used to a bigger bike I took it to a shop because one of my exhaust valves bent and got stuck open so I had a new one put it they shimmed all the valves and left one a little tight but the bike still has no compression so I had a diagnosis done and they told me the shims were off and I needed a new fuel pump so I shimmed them again and put a new pump in when I took it back after that because it still had no compression they told me my motor was blown and it would be around two thousand to fix so I was looking at getting a crate motor but I have no clue what year the motor mounts and frame got changed if anyone could help me with either finding something to try or with a year that a new engine would fit I would really appreciate it.

[Back2-2]

Hello, The very first thing you need to determine is what is "blown" about the engine. That term is so vague and has really no merit to the problem.
If you have no compression it's time to figure out why. Valves, cam or piston and rings? If the lower end of the engine is fine you can easily fix the top end for far under $2000. With a manual and some skills and taking your time you could buy from Ken here on the site a complete head assy and install it or have yours rebuilt. Piston & rings are very reasonable also.

I think the best thing you can do right now is stay away from the shop you have been going to.

[timmy2648]

Thank you and they told me the whole engine bottom and top end would need to be rebuilt and I noticed as I was looking into it more the exhaust is sucking in air and I don’t think it’s supposed to do that but the valve was bent in the seat could the bent part of the valve being in the seat of caused the seat to be messed up from that

[Back2-2]

I would certainly look into it myself. Why would they have you replace a couple items before determining that both the lower and top end are bad? Something is not right. If you pull the top end you can rotate the lower end and just get a feel of it and do some measurements to see what the side play and rotation is like.
The lower ends are pretty robust unless they become contaminate from a top end failure.

[timmy2648]

I would certainly look into it myself. Why would they have you replace a couple items before determining that both the lower and top end are bad? Something is not right. If you pull the top end you can rotate the lower end and just get a feel of it and do some measurements to see what the side play and rotation is like.
The lower ends are pretty robust unless they become contaminate from a top end failure.

I have looked into it but a intake valve feels to tight and everything else seems to be okay to me other than that I’ve took the head off and the piston and cylinder look good too but the bike still won’t start and has a very small amount of compression from what I’ve researched too I’ve heard that the gasket between the head and the cylinder may be not making a seal and cause the exhaust to suck air in instead of just blowing it out

[Back2-2]

That is correct. But you have to fix the valve problems before even trying to start the engine. I suggest pulling the cylinder off, check the lower end and inspect by gauging everything from the lower rod & crank up.

[timmy2648]

That is correct. But you have to fix the valve problems before even trying to start the engine. I suggest pulling the cylinder off, check the lower end and inspect by gauging everything from the lower rod & crank up.

How could I test the valves before starting it I know that the spacing is right for three of them just one intake is really tight when I used a feeler gauge

[Back2-2]

Yes, that is what I am referring to. That has to be corrected - It's shot. The valve is recessed into the head leaving zero gap. The others are probably right behind it.

[Aussiecrf230]

Reshim the tight valve and it will probably run.
But once the valves start to go you will only get a short run time before they zero out again.

If the smallest shim won't go in to fix problem then, as Neil said it is time for a head rebuild at least.

[timmy2648]

Yes, that is what I am referring to. That has to be corrected - It's shot. The valve is recessed into the head leaving zero gap. The others are probably right behind it.

Is there a way for me to rebuild the head or do I have to take it somewhere then and if so is there a place in the palm beach area in Florida that you guys know of because the places where I took my bike I feel are overpriced for what the cost is for parts themselves

[Back2-2]

If you want it done right and done so you do not have to mess with it again - Send it in to Ken, owner of this site. He has all the high end CNC equipment to do it right. I had him do mine and could not be happier with his work. I would also do a piston & rings while its apart. Use Honda OEM parts.
These are highly tuned 4 stroke engines that are not like the old days of just lapping in some valves on bikes.

[timmy2648]

If you want it done right and done so you do not have to mess with it again - Send it in to Ken, owner of this site. He has all the high end CNC equipment to do it right. I had him do mine and could not be happier with his work. I would also do a piston & rings while its apart. Use Honda OEM parts.
These are highly tuned 4 stroke engines that are not like the old days of just lapping in some valves on bikes.

is there a way for me to contact him because it may just be me but this site is really confusing to me

[Back2-2]

On the right hand side of the home page there are three boxes and one is "head Service" that will direct you to all Ken's machine work he does and prices. There is also a "contact us" option on different pages. If you still have trouble let me know and I can put you in direct contact with him.
I know it's a little confusing but if you bear with it Ken can get you fixed up.

[timmy2648]

On the right hand side of the home page there are three boxes and one is "head Service" that will direct you to all Ken's machine work he does and prices. There is also a "contact us" option on different pages. If you still have trouble let me know and I can put you in direct contact with him.
I know it's a little confusing but if you bear with it Ken can get you fixed up.

I just want to give a big thank you for all the help sense we last talked I have got the valves reseated and cut and put in a new fuel pump fuel filter air filter and injector and tonight it started up for the first time since it blew up the top end to be honest I didn't expect it to ever start again but from your guidance on what to do you also gave me hope that there was just a chance I could get it to run again I can't say thank you enough for all the help it means the world to me

[Back2-2]

Excellent. Glad you are up and going. These bikes are to nice to just junk them out when there is a mechanical issue that can be resolved.
Safe riding.